It's an occupational hazard for executioners that a pardon may arrive too late. Someone's going to get yelled at. Hopefully it's not Bart.

When Bart get called in to eat someone in his occasional role as executioner and body disposal for the city, he has to stay in the Guard HQ for the rest of his shift. He's always either locked in a cell or guarded to prevent any last minute escape attempts by allies of the condemned.

8-10 hours isn't enough for him to completely digest a human sized meal but it does more than enough damage that the less powerful flavors of Resurrection magic won't work even if he coughs up his partially digested prey or is cut open once he leaves the HQ.

Anyone with friends powerful enough to provide truly powerful Resurrection magic (that would bring them back from as little as a lock or hair or from badger poop) is dealt with by more extreme means than sending them on a short trip through Bart's guts. That sort of person is hard to get rid of. Bart is just a convenient, and most importantly cheap, way to (probably) permanently get rid of mid-range troublemakers.

It's a good deal for Bart. He gets a meal, he gets to laze around reading and napping as he digests the condemned, and he gets the next day off too to finish digesting them. Getting paid to hang out in a cell or inn while you sleep off a meal is a good job if you can get it.