I would suggest not giving them any weapons or they will murder all your dorfs for failed production orders.
^^ This.
I had a revolt in one of my 31.05 fortresses where the newly elected immigrant Mayor issued beating orders for all of the original seven for carrying -Orthoclase Mug-s to the Trade Depot. As my "guard" was armed with *Steel BattleAxe*s, they went around beheading the founding dwarfs. It looked rather like a coup... but I know that's just normal dwarf behaviour.... It also produced my first tantrum spiral of 31.x.
I had a similar happening in my first fully functioning fort. After an ambush of an FB from the depths of the caverns, I quickly started forming a fortress guard to stop the thing from killing my dwarves dead. The only two were a wrestler who frankly got torn in half two seconds later when he walked into the giant otter's path, and my original miner, who had now become legendary. She immediately embedded her pick into the thing and killed it (Although not before it took down 14 of my 35 dwarves with it). AWESOME. THE FORT IS SAVED.
My new guard began to parade about the fort, which was full of tantruming, grieving dwarves, Putting her pick into the head or throat of any person that would do no less than take a quick swing at a cow. The fort slowly gained up to about 6 casualties to her tyranny before I caught a look at a report of it.
NOT SO AWESOME. THE FORT IS UNSAVED.
And well, you can figure how it went from there.