Why does Rush, the trio from Toronto, always have washing machines on their stage?

"Geddy uses ear-pieces to hear himself so in place of amps, he has washing machines." It's just for humor.

http://heylivemusic.com/content/rush-rock-n-rolls-most-memorable-stage-props-features-part-2

"Geddy no longer uses actual amplifiers on stage. He uses something called "Sans-Amp" which basically let's him process his sound just as if he had an amp on stage, but it goes directly to the sound board. He didn't want his side of the stage to seem empty so he decided to put dryers on stage, just as a joke. For the R30 tour he added a snack machine as well."

http://www.avsforum.com/avs-vb/showthread.php?t=674178