Then I'll be a dick and modify the client to take the frames anyway and still send a reject. It's going to be abused.
Seriously though, any platform is going to have its share of liars, cheaters, grifters, con artists, and outright scams. What the world relies on is that enough people aren't. The trick is attracting enough honest people while driving away enough of the dishonest people. it's a constant game of cat and mouse.
Better yet, make all abusers render each other frames.