Many people find it hard to suspend disbelief. In training for acting at ren-faires a lot of work goes into this - both for the actors themselves and to teach them how to extend that suspension to the patrons with whom they will be interacting.

One of the interesting things about working ren-faire is observing the different levels of suspension of disbelief that people operate from.

(from which people operate. that participle is actually dangling - it's suspended from my disbelief)