Yep Gigi, my belly bands are branded 'bellybrites' and they're the same sort of thing as those 'mumstums', cept mine have a different colour on each side.

I use them with my fave jeans, leave the button and half the fly undone and hide it with the belly band!

Also, if I ever develop a belly , (people who joked about it at 15 weeks are starting to look concerned at almost 18 weeks 'are you sure you're pregnant?') I reckon the belly bands will be helpful if there's a gap between a top and skirt/pants.
Or just to keep my belly warmer in winter, if I'm wearing one of those cardigans that won't reach around my tummy.