What about violence and theft ? I know that nowhere is perfectly safe,but has anyone had bad experiances with these problems.
I've never had anything stolen, but I my campmate has. Theft does occur, usually on the spur of the moment when tempting items are left out flapping in the breeze, or right inside unlocked car doors, so lock up valuables out of sight in your vehicle, keep the key on you securely or well-hidden in camp, and consider a spare, as locksmiths are expensive.
Lock your bike (at minimum, lock it to itself) and drag it out of the way, as drunks will mistake it for their own, or be really tired and a mile from home and just "borrow" the easiest one to steal. I think a sizeable number of the bikes left on the playa every year were borrowed and then abandoned in embarrassment when people sobered up.
It's the same measures you would want to take in any town of the same size.
Violence seems infrequent, to me. I literally haven't seen any, though I know others have. I get the impression that domestic violence is the biggest risk--couples already on the edge, tested by the challenging environment, drugs and temptation. I see more threatening behavior from citizens in my own reasonably low crime hometown than I do in the desert.
It's not lawless, mind you, despite the nude people and the open containers--there are cops and Rangers, and people look out for each other as well. But it's also a certain amount of self-selection for who attends. These are not bored young men on a Friday, looking for a fight. These are people who have worked hard all year to get to the desert & be happy, and you really see it on most every face when you're there.