Then have them create their own account! No, I would not give anyone access to my account. Some on here have told stories of woe because they did that and got screwed by the person they gave access to. Plus, it just becomes confusing on who is actually posting each question/opinion/comment. Let them get their own account.
Nope there are plenty of hackers out there that can and will steal your account if the door is left open for them and it happens many many times, those low life hackers spend hours and hours trying to find those accounts and they will steal all that is in it in a heartbeat and can even portray you and make you feel pretty crappy when you do find out it was hacked.. so to answer your question.. not under any circumstances would I give a person nothing to do with my account.. I just want to make sure no one ever gets it as I have been hacked twice now