So I just took a trip to Mexico for a friend's wedding this past weekend and experienced for the first time the beeping metal detector. I have traveled with my wigs on through airport security before never beeping but this time I was. I knew once I took the bobby pin out of my wig and still beeped that it had to do with the bobby pins I have underneath my hair to keep the wig from sliding. SO I told him I wore a wig for medical reasons in a low voice. He said ok no problem and directed me to the little glass booth where a lovely lady came by to check my feet and pat me down. I told her about my wig as well and her response was, 'Really?!? What is that human hair? Amazing." She told me the only thing beeping was my head and bra and sent me on my way. It was all of 1 minute and truly it wasn't that bad. Not a single person had a clue what was going on - so many people have jewelry they forget about that causes it to beep. What I loved is they didn't make me remove my wig or even show them where the clips were. They were very sensitive and accommodating.
My big fear was coming back and going through security in Mexico since there is a little language barrier and I didn't know if they would be as accommodating. I chose not to wear the bobby pins underneath and just used the regular clips attacher and not a single beep was heard. So don't worry ladies and gents! Just don't wear bobby pins! :)