Is it "protecting kids from themselves"? Besides the fact of whether you want to do this or not, many kids will have access to their parents' or friends laptops anyway.
Are you trying to cover your ass if they do something dumb? Just trust the damn students. Put the responsibility on them: if they accept the laptop, they accept that they have to decide what is "good, moral, proper" etc. to do on the laptop, with all the consequences of it. If you start policing, you're basically implicitly assuming responsibility for the kids, not allowing them to take responsibility, or for the parents to teach them responsibility. When you do screw up and let the kids download child porn, it'll be all on your head.