Hmm, let me try that again. I think what I’m trying to say, without sounding so accusatory or dismissing, is that a society’s crimes are dependent on its unique situation. Crimes result from the complex interaction of needs and wants versus upbringing, circumstance, culture, genetics, etc. On a macro level, how your particular utopia exists dictates how it will fall – what is it about its people and their living situation that makes it a utopia? Answer that first and you can start to look for things that somebody, somewhere is going to dislike and try to change.
Does your utopia remain so by way of some sort of fascist government or mind control? If so, popular fiction dictates that somebody out of the 100k eventually stumbles upon “the ugly truth” and enlightens the people by telling them that their shallow happiness is not as good as the harsher reality, whatever that may be.
But they all have everything they need, you say? Well, can that ever really be the case when you have 100k people? There are always individuals who want more, more, more, whether it’s greed or something as basic as lust. Where there’s reproduction there’s competition, and as long as your society still abides by normal human breeding patterns, people are going to try to out-do each other just for the better mates. Crimes of passion would probably still happen.
Is it some sort of socialist paradise where everyone works productively and has a comfortable, fair life? Some young kid somewhere is going to want more adventure, fame, power, or women, and get himself into trouble. A kinder disposition may limit the intensity of actions, but it normally doesn’t eliminate wants altogether. Over time and generations, things are bound to happen.
And the thing about a society of 100k is that even something as basic as genetic variability is bound to throw in a bunch of confounding variables over time; psychological screening is hardly perfect enough to choose 100,000 people whose offspring will forever be docile and cooperative.
Essentially, it’s not so much “Will crime happen?”, but “Which crimes, and when?” – and that depends very much on the nuances of your particular vision of this utopia.