I've never done this, or even heard of it being done, but has anybody used a "fine" system, where anybody who doesn't know their part (or maybe commits some other offense against the band's best interests) puts a dollar into a band kitty?
That only works if there is a lot of money flowing in the band. Working 7 nights a week, getting paid for every night. ie. cruise ship band, casino house band, theatre pit band etc... usually the fines are "beer fines" or something that the band enjoys.
Long ago, famous people making money did do that, like Ike Turner and James Brown... maybe it is still done now... but really, the money has to be flowing in for everyone, in order for this to work.
Or, everyone has great day jobs, and the band is a fun social club, and people put money into the kitty and have fun with it later. The fine system being part of the fun.