The rules of the game jam state the following: "You and your team are encouraged to make everything from scratch during the event. If you use any pre-made assets you must list them in the description of the game and you must have the rights to use said assets."
Off the top of my head I can think of at least 5 different submissions that breach these rules, using assets the developer clearly doesn't own or just reposting an older game with a leaderboard stapled on (sometimes with the original version of the game left on their page) and having no mention of this in the description or anything. Will any measures be taken in terms of quality control or do legit devs have to contend with this?