I don't see anything right with it!
I don't know the dynamic at work with the One Love Pub Crawl Bus, and don't want to speculate on who benefits from the higher prices, but I would not want to patronize an establishment that temporarily raises prices because a busload of tourists pulls up.
(I have witnessed this happen on JUTA shuttles from the Sangster airport to Negril, and I don't buy anything at a shop if I believe they have inflated prices based on the customers they see before them). In fairness to JUTA shuttles, they have also stopped at shops that don't raise their prices.