Let's suppose we're taking sane humans into the ship, then crime wouldn't be a problem. People tend to turn to a crime-dependant life when they lack something. In this ship they'd have food, shelter, fun and people to socialize with. So I guess all the basic needs are satisfied. To prevent boredom, they'd need something to distract themselves, to challenge them in a physical and psychological way. I suppose current technology could already be used to challenge these people continuously. So next "issue", would be quarrels/fights, which I think could be fairly common by people misunderstanding each other or saying something a bit more mean and not controlling themselves (in words and actions). If people nearby would help to end the fight, then it wouldn't be a problem. This really depends on the mentality of people in the ship. Probably one of the biggest issues would be people abusing their available resources. So unless everyone in the ship(in 250k people I think it could be hard) would know when to stop drinking, eating, or doing any other thing that someone can get addicted to, that could become a problem. Unfortunately I don't think people would make it to Earth mk2 without control and rules. So actually a militarized "way of life", just like Themohawkninja said, would be best. The chain of command would help maintain people in their places not do anything against the rules (they'd be sent to a court otherwise). Also they'd be kept busy with useless work(when there's no war, keep them busy). Of course that wouldn't prevent everyone from making "mistakes", but I guess it would be the lesser evil (if I could say so). Still, I'm just supposing this ship would have a society like the ones we have on earth.