Nope, friends and family are welcome to use it, nothing stopping them using it and I have no problems with them doing so. Plus my friends are not really into gaming or drinking (I drink the most out of all of them. )
If my sister asks..haha..forget about it. No way she's getting on my comp. My bro's I'll occasionly let on if they have a good reason. As for my parents, if they ask I don't have much of a choice because they're the type of parents that don't take "no" as an answer. Not to mention, if I tell them "no" then they'll think I'm hiding something....aye...my parents are already suspicious enough as it is.
Close friends I'll let on, but I keep a close eye on 'em.
I agree with what Harper said earlier about not wanting people to mess with his settings, that's why I don't let anyone use my rig. My parents have a PC in the family room for them to use and I used to have to use it before I got my own rig and I hated it, reason I hated it is cause it's a celeron, I put a lot of time into tuning the settings on my rig to get them how they are and neither of my parents know how to use a pc all too well. My dad still asks me "So i just type in the website name and hit enter and it'll take me to the site?" every time he uses the computer and my mom only knows how to use macs so letting them mess with my rig is a definite no.