I could ALMOST understand if it was optional. If you don't pay the fee, you don't get ME, Magic Bands, etc. But resort fees are never optional.
At Swan and Dolphin they used to be. You'd get a newspaper and I forget what else for the fee but one could waive it. We always did but sometimes we still got the paper. At that time self parking was free at S/D too. I know S/D is only associated with WDW but I still consider them to be 'onsite'.
Bill From PA