Is that a toupee??

While visiting London I was riding on  the lower level of a doubledecker bus.  A bunch of about 8 teens came down the little stairway from the upper deck. As soon as the first one saw me he turned and said something to the others.  They all came and stood just over me, and the first one said, "IS THAT A TOUPEE"?  I ignored him.  He asked it again, louder.  People were looking.  I pretended not to notice (here the hearing aids come in handy), hoping no one would know it was me. He and some of the others kept asking, "IS THAT A TOUPEE"?  Finally I got off the bus!