Harry has a wild side to him, we've all seen it time and time again. And lets face it any 18, 19, 20 year old in his position would most likely behave very simialrly. Harry can chose to be discreet, but lets face it, whether he is behaving himself like a "little Prince" should, or being the way he is now, the press is going to find some reason to follow him. I agree that many of his actions are distasteful, and I do still think that many times Harry courts the press (this incident I don't believe is one of those times.) The world took an interest in Harry and his brother at a young age, much because of the actions their mother took. Diana, I believe, in her attempt to gain the upper hand in her battle with Charles, used her boys when it was convient to her. If using them for good press was what she needed then she did it. I'm not doubting her love, I don't think anyone could, she adored those boys, but she also adored public attention and was very good at manipulations. Because of her manipulations of the press her boys must now deal with them, long after she is gone.
William and Harry would have always been in the public eye, they were born into it, but I think without their mothers courting early in their life, they would have been given more freedom now. Instead, their mother died while being pursued by photographers, they were captured by the world in their grieving process, and people fell in love with the two vulerable young men. Now the world wants to know how they are coping, what they are doing, which is a totally natural human response, and both young men have chosen different paths as to how to go about dealing with the ever present press. William chose to go to school and hide himself away from the world. Harry it seems realized there was no getting away from it, and is choosing to try and live his life his way (whether that way be good or bad is obviously up for debate!) and it seems trying to just be happy his way and not by the standards set by others.
I'm not defending all of Harry's actions, but I agree with Dreamcatchgirl in giving the boys a little room to move. They didn't ask to be put in these positions, and while they need to realize that they are always going to be in the public eye and should act accordingly, they should also be given the room to make the mistakes that every young person does. In his position, I too probably would have lashed out at the press. I have friends who have done it before. The paparazzi aren't innocent in this, they don't know when enough is enough, and they keep pushing and mobbing, and in the end people break-which is what I believe happened to Harry-he broke. In the end every teenager drinks when given the opportunity. It's part of life. Part of the college life (at least here in the States) is partying and hooking up with many members of the opposite sex. Harry's love life is considered free game to the press. If they weren't constantly around then no one would know or care about who Harry kissed-but they are and so the world knows. (Yes-though-he should use some brain power and realize that making out in public is what is going to be splashed across newspapers far and wide).
The cheating on the exam thing really had nothing to do with Harry-he was just a pawn in the teachers game to get back at Eton, and she knew Harry would make the most waves and cause the most damage.