Thanks for bringing up the topic!
And unfortunately that is the tip of the iceberg. Those acts are so common, that even at times they are initiated by the Dr himself, asking for specific compensation in return. That no longer classifies as a gift, it's seriously a bribe! 
In our region here, the effects might be further worse, with Drs prescribing "unneeded" medications for some patients. We are talking oncology cases!
Sadly in a profession such as medicine, where ethics and integrity are much needed, I believe many Drs just forget about their oath.