I feel real sorry for the first 21 y/o boy...that comes sniffing around my daughters...or a 21 y/o female that tries to come sniffing around my 16 y/o son.
I only have daugters, but when they get older if anything like that happens, my response will quite possibly involve a blowtorch, a pair of pliers, a ball peen hammer and a shovel.
When my little girl turns teen-aged, any prospective boyfriends are going to get the
Lethal Weapon treatment from Dad. Dad's going to take said candidate shooting. Dad's going to send a standard B-21 (torso) target downrange. Then, Dad's going to shoot it seven times, so that when said B-21 torso target is examined, it will have two eyes, a nose, and a smile on it from the seven rounds I shoot. Then, said candidate is going to be presented the B-21 target, with the words, "Please be nice to my daughter."

Hopefully, she won't hate me.