Prison would be too easy.
I purposely put one of my chracters into badsport for two days recently just to see how much crap i had to do to get in.
120 cars and two days later. Boom in Bad Sport. All it has are other bad sports and cheaters.
Don't bother going into a mission in bad sport. Most of the idiots there think that walking in a mission puts the timer down faster. Its the equivalent of putting yourself in your apartment and turning on passive mode.
So real prison would be. Having to complete one Simeon delivery every hour of bad sports time. So 2 days of bad sport would net into 48 cars that need to be exported. So even if they just wait 2 days of doing nothing they still have to deliver 48 cars successfully. Also while in bad sport for every car you destroy. It adds two cars you need to deliver to the list.