I have similar thoughts in terms of EV charging to park guests without people just chucking their cars in a spot for the whole day. It's hard to incentivise someone to head out of the park when they've paid £150+ as a family of 4 to get on and park on the first place. As EV use grows I don't think that's all that sustainable. It risks causing more complaints from guests than the current complete lack of chargers. At least EV drivers know where they stand at the moment.
There's only a finite amount of infrastructure to support charging at Towers, so it needs a lot more involved thinking than "just add more chargers". If only they had sufficient capacity in the hotels they could've had some sort of offer where people could have a drink, maybe grab some post park grub, quick charge their car to be on their way.
Of course that again comes with limits, so perhaps linking up with some nearby facilities and publicising them as an alternative would be a good idea too? Incentivise people to top up before/after their day at the park instead with some sort of discount/offer?