3) unwanted / rejected / opted-out donations will be returned to the 'project pool' instead of the donor, it's unclear what happens in cases when a project has no participating developers (default), is itself opted out, or has all opted-out developers

4) donors are not informed that the projects they're supporting may not receive or accept donations this way

5) donors are actively lied to, see:

https://tip4commit.com/github/django/django

and

https://news.ycombinator.com/item?id=8545377

has a django rep trying to opt them out of the program, there is no ambiguity whether they like, let alone want to or will receive donations this way