The "why" is probabably more important than anything else. I believe that teens push all the boundaries of their world in a simple, primal, search for absolutes. I am always surprised at how often they express relief when they get busted - but if you see it as a clear line in the OK/not OK discovery process, rather than a rather simplistic or moralistic "wrong". It can help both you and them.
The solution is then three-fold. One, does he/she recognize that their action was inappropriate? Two, does he/she realize the repurcussions of their actions? (Don't assume they do) and Three, is there a way to minimize the repurcussions? (fix it if possible.)
Paying it back fixes point three to a large extent, but points one and two need some thought. It is a difficult conversation, but might be the most important. If a teen walks away from the event with the thought that is wrong because my Mom thinks it is, the emphasis is then "don't get caught", rather than, "this is not OK."
The only real "fix" is when the transgressor genuinely accepts their transgression.
This is based on thirty years of living/working with teens, during which time I learned that discipline needs to a be a learning experience AND have a meaningful consequence.
Oh, and dont forget to tell him/her that you love them, it's just the behavior you don't like...