bhanks foolish idiot is not a serious lifter so he doesn't know about such things, but no serious powerlifting organization allows straps during the deadlift. It's fine to train with straps, that's a fairly common "overload" technique, but a demonstration of competitive strength needs to be done without straps.
Most of them allow normal-sized belts in "raw" competitions. I'm not aware of any that disallow belts but there may be some.