I agree with TahitiBoy's comment about forgetting his nametag. I used to always do this and many times would just wear someone else's if I left mine at home.
Towards the end of my employment when I didn't care, I wouldn't put my nametag on until I actually got to the front desk, and as soon as my shift was over, my nametag came off. I figured no nametag, no guests asking me stupid questions (didn't help though)
I've since regretted acting like an arse-hole, but I was young then