The credit is distributed by the projects, so I suppose that could in theory be cheated by the project admins. Gridcoin is distributed entirely autonomously based on those credit numbers. Therefore, the Gridcoin proportion of the payout chain is trustless ([all the source code is on github](https://github.com/gridcoin/Gridcoin-Research)).

At worst, a project admin would be able to give one user infinite credits on a regular basis, and the Gridcoin network would then pay out:

[1/number_of_projects]*daily_GRC_mint

to that user. So, yes, there is some potential for abuse. It will never happen though as:

- Projects are carefully vetted before being eligible for reward. This is based on a community vote adding the project to the rewards 'whitelist'.

- The project admins are researchers that want BOINC and Gridcoin members to help them complete their studies. They have no motivation to cheat the system (plus it would be pretty obvious).

I am not sure I entirely understand the second part of your comment. The Gridcoin network does both. Primarily, it 'mines' through BOINC work but the network is additionally secured by a POS system which continues to function even if BOINC is 100% down.