15 minute timer in between game review would be great and if the player has not downloaded the non Web GL game, they should not be allowed to comment or rate the games.
I wouldn't be surprised if they have such as system on itch.io since they host so many jams. In a database (which this whole jam is in essence) a simple cluster analysis (common method to determine insurance fraud) would uncover every suspicious transaction (in our case rating) instantly. I simply don't know if such a tool is available to the hosts, since I never hosted a jam myself and have no clue about the back end.
But I would never implement a hard timer. Not only would this give you tons of false positives, it is just going to make some people pissed.
Well what can I say, accept that I am that guy that reads the license agreement in full before installing the software. I try to improve, I really do.
Since I have nothing better to do and I want to improve my c# I will actually try to make a monitoring API. A rudimentary one, but we don't need a lot.
I'm a bit envious of you as I just read the headers of TOS sometimes when installing application in my PC. If you are focused on self improvement I think you will definitely have a lot of success in your lifetime, maybe you already do.
If you manage to make that monitoring API, I think itch.io will definitely take an interest and it will help to make the game jams alot better experience for everyone. :D