We have had this discussion over the years many times. But I think wearing a belt is about like wearing a shirt with a collar on it. Or as a football official or baseball umpire you show up with adjustable hat. No one at the upper levels wear belted pants any more. They are not featured anymore in the major officiating catalogs. Not saying you cannot get them, but the beltless pants are the main sellers for basketball officials in those catalogs. It might not apply to all areas, but if you wear belted pants for a game, it is one of those signs that shows you do not pay attention to detail on many other aspects of your officiating (in my opinion and many other officials I know). Bottom line it comes down to professionalism for me.
You can find pants that fit in most cases. And if you need them adjusted, go to a tailor.
Peace