well, we can't fully rule out future regulatory bans on crypto but i believe there is a very small chance of that happening since so many companies/gov'ts are starting to look into it.
What might shadow the regulatory ban is corporations taking over the blockchain tech and offering better, more trusted solutions in terms of technology compared to the community driven ones. Corporations are fierce when it comes to engulfing markets that produce revenue.

 I think the Y/N thing for US citizens is more to motivate some people to add pressure on SEC.

A friend of mine sent this to me this morning an i find it as a good balanced view over investing in crypto and ICOs etc.: https://www.reddit.com/r/ethtrader/comments/6eo5fb/on_risk_and_valuation/

U.S. citizens are being shut out of so many investing and banking opportunities under the guise of protection.  It will be a good day when people are allowed to make their own decisions, whether they be wise ones of foolish.

Interesting idea.  Could a US citizen sue the ICO founders claiming discrimination based on incorrect facts (define "excessive")?  There is always the ubiquitous "void where prohibited by law" disclaimer on every advertisement, but prohibition by law is vastly different than excessively regulated by law.  Also, isn't the compliance with the excessive regulation the onus of the investor, not those offering the investment?
This definitely gets the brain thinking!

The problem is not the SEC, which has no jurisdiction over Mona.co or any other EU-based ICO. The problem is the IRS and FATCA, which requires US taxpayers AND financial institutions in tax-treaty countries to report all assets held abroad by said taxpayers. Many banks and other financial institutions abroad simply don't want to do business with Americans, because of the regulatory burden FATCA requires of them, and because the information demanded might in fact violate their own "house rules" about client confidentiality. 

So, Mona.co asked the question to screen out Americans. Otherwise, Mona.co might find it hard to get the EU licensing they need  to carry out their plans. They also might be obligated to return the American investors' funds, which is problem a hassle they don't want to have.

The Polybius Bank people also warned US taxpayers not to join in their ICO for the same reasons.

We need to convince Washington to rescind FATCA, as it has not proved to be effective in eliminating money laundering or  tax evasion. The fat cats can evade the law by creating shell companies and other clever machinery to hide their money. It's honest citizens who are being unduly discriminated against by FATCA, not the crooks.

Incidentally, I wrote about this same subject a couple of days ago.

Excellent post Dana - used it on Fakebook as reference with this prelude and then linking to this post ;-)

The crypto world has already elements of self-regulation which include measures to protect themselves from the monsters that the federal reserve system has created and/or is leveraging (like pentagon, SEC, IRS and the corrupt congress and elite in the District of Columbia)

Very broadly, There are two plays to be made right now:
1) Short term, "fast thinking" plays that pretend that the existing U.S. government can recover from having been destroyed. (These plays pretend that paper currency doesn't return to its intrinsic value, that the law is not corrupted, and that taxes should be paid and mala prohibita is likely to be, and should be, followed.) Of course, this is all simply extending the superficial lies used to rob us all blind.

2) Long-term "deep but slower thinking" plays that extend up until the "Singularity"(Vernor Vinge, Ray Kurzweil; John von Neumann) or "Intelligence Explosion"(I.J. Good), and perhaps help cause it. These plays must be 100% private, anonymous, and untraceable, and never-mappable to any police-cam, or knowable MAC address, anywhere. This means: If you've ever previously signed on to the internet with your computer, in any capacity, and interacted with any software, you can't use it for any crypto-currency trade. Morris's three rules apply. However, if all the opsec is followed carefully, these types of systems are vastly more useful and robust than the former. In fact, the former all take the form of a fast-moving scam, because the existing governments of the world are all "vastly superhuman parasites." ...If you think any of them are "the good guys" and you enter into the former type of arrangement, then you are at best an idiot, and at worst an evil idiot who is willing to lose all his investors' money.

IMO, there is not much they can do. The legality is such a grey area. The whole point is with crypto, you are anonymous (can be anonymous) in your utilization of otherwise illegal investment opportunities.

Good morning, I've followed you and I see you make a good post congratulations, follow me and we help each other

Well what happens if they choose to participate anyway?  They risk loosing their money or legal action?

rue enough but have you considered this:
with all the money in ICO and the US potentially cracking down...
https://steemit.com/sec/@felander/sec-to-persue-ico-and-token-sales-as-securities-will-this-lead-to-companies-relocating

i live in Switzerland, we welcome them in the crypto valley

As a US citizen I am currently working towards dual citizenship. In this day and age we have options to limit the control governments and bureaucracies have over us. The rush by governments and banks to move their control from existing system to the new paradigm that may replace them, is exactly what blockchain and cryptocurrency technology was designed to free us from. When I first got into crypto it seemed very much like the wild west. On the frontier things are bloody until they become settled and that is clearly where we are at with this. Whales and institutional investors trying to scare away those new to the market and take their money along the way. Get rich quick schemes by criminals and those looking to take advantage of the ICO scene with poor or not fully formed ideas. It is interesting to watch how things will eventually settle. Definitely an exciting shows!

Regarding the ICO opportunities for US investors. Some blocks can be bypassed as they only require you to acknowledge your country of origin but have no checks in place to verify. The serious ones require you to upload your passport and other documents. I am not sure how they verify legitimacy but it's another layer of protection. I understand it's easier for these companies to not do the work required to allow those countries with more strict regulations but it certainly is contrary to what the whole crypto movement is about. Will see how this eventually shakes out but I do believe the conversations being generated by this is a good thing.