easyJet introduced uniform for all sim events from 1st Oct 19 - professional standards was quoted as the reason as we started using our 3 new sim centres. In reality, think management had got quite frustrated that the attire some were deeming acceptable. T-shirts, ripped jeans, dirty trainers...had everyone worn smart jeans or chinos and a collared shirt, I doubt this change would have manifested itself. Instructors also now all in uniform too. Would be nice not to be in uniform but there are bigger fights to be had at present I think was the general consensus.
That's likely the reason rather than "enhanced realism."