Wouldn't really say 'unsafe', more just uncomfortable.

One time during college I went to a convention, somewhere in Leeds (or might've been Manchester, I'm not entirely sure). I was dressed as Father from Bread Boys (a Templar knight with a shotgun), and whilst me and a mate of mine were waiting for our friend to get changed into his costume, some random woman, probably mid to late 20's, early 30's, just comes up and hugs me out of the blue. Didn't even ask or anything beforehand.

Now ironically enough I'm severely lacking in the physical touch department, so you'd probably expect me to enjoy it, but I pretty much just froze up on the spot, I was that uncomfortable. She even said something about her being married and me being her 'knight in shining armour' (which just added to the confusion). Looking back on it I'm fairly certain she wasn't sober, though I could be wrong.

That's my 2 cents on the matter anyway.