Yeah, I get that, but taking the lesson away of "I won't seatbelt prisoners" is the wrong thing to do.
Shitty tactics get you hurt, don't use shitty tactics.
Not taking care of your prisoners can get you jammed up as well. One of my troops decided that he wasn't going to seatbelt his prisoners anymore (which I was unaware of because he did it when I was not around...), then one day he got into a wreck, bad guy in cuffs wasn't seatbelted in, got launched across the back seat area into the far side of the cage. Closed skull fracture and massive concussion. The check the city wrote for that one cost us half of the cop cars we could have bought that year.
"This is why we can't have nice things..."