It's actually a really good way to meet girls... When you can see they are very uncomfortable and the dude is relentless in his pursuit (or just daft at getting her "non interested" hint...
Just go up and say... I'm sooooo sorry for being late, can you forgive me ? gently take her arm and pull her away.... Then say... you looked like you needed a reason to leave the person hitting you, and say, if you want to stay and chat that's great or if you want to leave that's good too... 9 times out of 10 they will stay and chat with you... get a drink and you have them for longer... if she is the playful type tell her to kiss you so the guy that keeps looking over gets the message... but you have to tell her that she must lean over to give the kiss...and you say it has to be on the lips otherwise if on cheek it's just a "friend" kiss and he will still be trying to pull her later
you definitely get her contact details for being the "prince that saved her" plus it makes a good story for her friends to tell.... Or so I read it does