First of all, married or not married one must control one's emotions and respect the other person/half. For example, If my husband is doing something like this and one of his friends have seen us... his friend will be the first one to say that xyz's wife was so .......... that she was smooching and getting physical with her hubby in a public cafe. Which when i will hear will not like at all. Infact anyone will hear will feel so dis-respected.
Likewise if it is a girl (un-married), she should have this much regard that her family members (cousins, bro or aunts.... anybody) might spot her with somebody doing something, which will result in a total disaster. I am really amazed when i see young girls with boys in internet cafes and smooching behind the cabin dividers... if i can notice them, what if their family members do as well!!!
The boy should definitely respect the girl's morality as in our society 90% ppl will not at all accept such female who have been found dating or hanging out with boys!!!!
yes of course they can do whatever they want, its their personal life... but to tell u the truth, i think it is totally wrong!!!