I would also assume in that sort of situation they would be escorted to the pool by someone with more authority than the person scanning bands.
CM at gate is just told to only let those with a magicband (or card) proving they are staying at this resort in through that gate. So without a VIP escort the CM still isn't going to let the VIP in (or will let them in and then get someone senior over to check).
But a non-VIP guest staying in a presidential suite would still need all guests registered to enjoy all the amenities without any issues.
Basically this entire thread comes down to if you want to use the amenities of a resort, you need to be registered and hold a magicband/card that shows that. (Restaurants and shops are different)
There might be some weird occasions for VIP guests but I would think those would be the sort of guests who have a plaid vest tour guide CM with them in the park.