im pretty (very) liberal when it comes to love, but thatd be too much for me
id talk to her and say whats going on, she'd probably claim she was in love, id try to tactfully indicate that she was probably in love with the attention. if she wasnt accepting that, cos hey, shes only 16, id get the guys number and call him up and say, hello, i know you are probably some lonely old creature but if you come near my daughter again ur gonna be taking your teeth home in your hat