I think it's natural for a kid to look at the number of athletes already at his position. His initial reaction could be...
1) He saw other QBs offered/committing and wonders if he's a fall-back
2) He wonders if he is viewed as a "soft" commitment with the other QB offers and questions whether the relationship is as solid as he would like
3) As an out-of-state kid, he may wonder whether or not he has the same chance to play/succeed as an in-state kid
4) Our offer/his commit opened up other offers he hadn't had/thought about and he wants to look and take visits
For every early commit where we all rejoice, we also have to be a little skeptical when a kid takes his first offer, or one of his first couple offers.
As someone mentioned above, as long as he is open/honest with the staff, then he should at least take those visits.
It happens every year. We end up losing out on some, thus, the late offers/commits we often see.