I was actually just about to point out that the term “sheltered” can mean different things. It can mean “not knowing things” or it can mean “not being exposed to things in an inappropriate way” (such as watching movies,etc.)
HockMaster, until I saw your last post, I was sure you meant the second meaning since having lived in Lakewood, I didn’t see it that way. But then again, it might depend who you know, and it’s all relative in any case.
If you had meant the second meaning, I would say it’s definitely better to be sheltered (and I think the Torah is quite clear on that). If you mean the first, I think it really depends on the person/family. I’m not sure if there’s a right or wrong here.
In terms of Yeshivas, everyone has to choose what’s right for him. There is no real right or wrong. The nisayon when one has a bad experience in one place and then finds a place that’s better for him is to remember that that doesn’t make the first place a bad place; it just means it wasn’t for you.
And by the way, there is no proof that kids who grow up more sheltered are more likely to go off the derech. I also don’t really believe that there are too many people who are so sheltered today that they don’t know enough about the world to realize that trash exists. I think it’s almost impossible to be that sheltered.