"Later designs would allow the threshold to rise quickly to combat the wizard-goes-to-the-cinema problem. The WGTTC problem is where a machine has adjusted down to a low replay score because it is mostly played by novices. "
a strange name though, how does a wizard going to a cinema reflect novices playing a pinball game?
Since these novices are not very good the replay score will be automatically tuned down on those machines. Which causes a problem if a "Wizard" starts playing on them since he will easily reach the replay score. Thus the machines need to be programmed to react quickly to a sudden increase in player skill level.
Since the replay score is set based on the top percentage of scores, if the majority of players in the movie theater (novices) lower the average score, a good player (wizard) is more easily at the high end of the score distribution, earning free plays consistently.