Sure they do. It doesn't seem to be a problem for credit card companies. Even Gmail seems to want an active phone line before setting up a simple email account. The reality is Facebook turns a blind eye to underage users. Those children are Facebook's bread-n-butter. I am still shocked they haven't been hit with fines or sanctions for continually violating the U.S. federal law that states people under 13 (or is it 14?)can't be monitored online.
Parents should be monitor their kids
Easier said, than done. Without paid body guards it is impossible to monitor someone 24/7.