You should carry an extra. I take an extra shirt along in my gear bag, and extra other stuff in my car.
Guys at my gym don't wear a cup anywhere near as often as they should, from what I can tell, and then they bitch and moan about low kicks or w/e.
My dog is crashing around, up and down the stairs, finding everybody with a big smile on his face. I R HUGGIN HIM!!
I usually do in my car so if i forget to put it in my bag theres one in the car... but my car is busted and im driving my moms car around