There are ways to combat the queues that help everyone though, rather than those willing to pay...
The constant upselling in parks is very different to be offered a £1 chocolate bar in Smiths, I've not paid £50 for the privilege of being in Smiths for one, which is why a lot of complaints at the cost of the park seem levied towards cost of food, car park and Fastrack...
Rather than bombard people with offers, perhaps improving the experience of everyone would help? Nicer queues, better atmosphere, some of the more basic theme park solutions would be better than pop ups on your park app...