Iv used this opinion opener a few times and infact a girl orginally asked me this question, not to sure if she was hitting on me or not..
Im aware that this opener will probably only work in the UK and aimed at 18-22 year olds (not to sure how succesful the groups have been in other countries). However you could maybe change it to any similar boybands.

All you do is go up to the potential set and say something like:
"i have been having a huge debate/arguement with some girls i came out with tonight... whos better busted or mcfly"?

Girls seem to be very opinionated on boybands so they generally reply enthusiastically .

However im struggling to think of a potential neg to their response apart from "your one of those girls then" which is quite generic, any ideas?

shoegazer

p.s i just want to state i hate busted and mcfly so dont worry im not into that sort of music!