personaly, i think banning texting only delays a potential problem, rather than educate teens/kids in the proper usage of anything (why is it any different than internet … if anything, internet is worse)
however, the dangers of texting are real, and any smart parent will know what their kids are up to (if you have good communication with your kids this should not be an issue … if you don’t, work on it)
be that as it may, mazca, what are you thinking … i am not opposed to boys getting involved with girls as a general rule (there are halachic issues, and they must be avoided/taken care of), but if parents don’t know, that is a dangerous thing … i would even go as far as to say that you have a chiyuv to tell the parents, or someone in a state of authority who would know how to deal with it properly