I would prefer is someone told me. I'd be much more embrassed the longer that situation went on.

It makes no difference to me if the person telling me had been a man or woman.

Perhaps you could have said something to one of her friends, left, and had her friend tell her.

I once saw a girl in Vegas with a similar problem. She was showing off boobs so new the price tag was still on them....bending over and acting like such a little snot that I just shouted from about 20 feet away:

"Hey, you...Boobs! Yeah, you....you got a little problem with your string!"

She rushed off to take care of it right away.....