The only potential risk I see with anonymous voting is some 4chaner is apt to create a bunch of fish with horrific names and use distributed IPs to upvote them to the top. I guess regular moderation could filter that out.

Any button a human can touch is a vector for abuse...

IP based breaks users with CGNAT and people connecting from corporate networks

In those cases you'd be denied votes since someone else used them up

The first case would be an issue yes, although this app doesn't exactly strike me as something that an insane amount of people would be connecting to from corporate networks

It can work okay for apps that don't go to massive scale and where users aren't concentrated in the same place. The chance of another simultaneous user on your block/building/CGNAT isn't extremely likely.

CGNAT is used in places other than corporate networks.

I'm aware of that - I spoke to the corporate network part specifically as the post I was replying to specifically listed that in addition to CGNAT

You write with such whimsy, absolutely delightful :)