A workaround is to have no fortress guard or captain of the guard (or sheriff) (and perhaps demolish your jail). If you do, then nobody will be arrested or beaten. The nobles get a little miffed, but it's nowhere near the unhappiness penalty you get if someone engraves a dwarf's bedroom while they're asleep in it!
I actually forbid the Guard as a matter of course, and have been doing so ever since my last fort in the 2d version. In the 2d version, I had executed the CoG/sheriff, and the hammerer, whenever they showed up on the map. Fortunately, in the current version, you can choose not to appoint a sheriff / captain of the guard, and the hammerer and royal guard have been nice and tame (presumably because I have no CoG or jail).
I originally began executing them, and all useless nobles, after one of the nobles in my last fort in the 2d version ordered my legendary swordmaster (who had singlehandedly killed a bronze colossus) maimed and jailed for "violation of production order," leaving him bedridden for the rest of his life.
Nowadays it's much easier to ensure that the nobles cannot maim or jail dwarves. IMHO, the nobles should be the ones getting jailed for demanding that we "MAKE LEAD ITEMS EVEN THOUGH THERE IS NO GALENA ANYWHERE IN THIS MOUNTAIN" and the like.
I do wish we could designate any dwarf as an 'enemy of the state' to be shot on sight by any military dwarves who see them, though.
[ November 22, 2007: Message edited by: Shadowlord ]