I don't think John should do this because he doesn't know if it's a spammer using his friend's name. He doesn't know for sure if the medicine really works, and maybe the file attachment is a virus. You should not open files if you do not know what is inside.

the video is trying to say that you shouldn't put your real name on public websites because whoever goes on that website will know what your name is. You also shouldn't put your address, phone number etc., because then people will know where you live and your other personal details. :0 that is NOT good.