I'll be interested to see how this unfolds. We aren't going until October, so hopefully Disney will see how petty they are being and change the rules before then!
Kenny was probably allowed to honor any standing reservations in terms of his prior method of order fulfillment. Once the new policy was put in place with WDW, any new orders have to follow the off-site pickup policy.
To WDW it's probably all about "who" initiates the delivery. A guest using a guest MB/KTTW card is permitted to bring in a cart. Kenny is not an overnight guest so he falls into another category. That's why in my reply above I noted that Disney won't turn down a guest who brings one in.
As far as the damage question due to back-to-back rentals, that had already been addressed.
Maybe this policy change explains Kenny's recent service issues with Disney hassling him and making life difficult. It will be interesting to see if those service issues actually diminish with the new policy. Kenny constituted the 2nd tier providers (Disney being 1st tier and others a distant 3rd tier). I mean, as long as the pick up point isn't in Lakeland, it's still a deal.
And as far as Disney being petty, you're right. They absolutely are. This is all about money. Given the confiscatory rates they charge for their own golf carts, Kenny represented a chunk of "lost" revenue that WDW wants to get back a big piece of. This is not like the trailer rental folks they let in to set up a trailer for you - WDW is not in that business so there is no competition. That service actually helps them rent more campsites.
But Kenny was competition so he was a threat that was dealt with. Which is why he can't bring the carts into the Fort, but you can. So I doubt the policy will change back. This has actually been a long time in coming.
Bama Ed