While I agree they need to be punished, jail time ain't gonna happen. Just because they face up to 5 years in jail and a 5K dollar fine, they aren't going to get it. These guys appear to be 1st time offenders.
The underlying charge, which they should be penalized for, is 1st degree felony Stupidity. And the punishment has already started. They are being publicly humiliated across the nation even before the trial. I am sure the insurance company where Dumbo filed for comp will take an interested how a guy with a bad back can flip a boulder.
An appropriate punishment would be a monetary one, and then sentencing them to community service picking up trash and cleaning out the public restrooms. Or maybe 100 hours of rolling boulders. And keep the crime a felony. A felony conviction is the gift that keeps on giving. It will follow them everywhere.