"Your expected wait time is 45 minutes..." And then after a brief moment, the same voice comes on and says "We've cut your time in half. It's just 20 minutes now!"
According to a 1989 Newsweek article: The waiting times posted by each attraction are generously overestimated, so that one comes away mysteriously grateful for having hung around 20 minutes for a 58-second twirl in the Alice in Wonderland teacups.
Source: http://dspace.mit.edu/bitstream/handle/1721.1/37703/21793670...
I am still ambivalent about that, though.
For any kind of interaction which may be repeated then it just makes you look like a stupid business owner or software developer who can't properly estimate how long something will take!