I have 2 sealth sightings of macs at The Kennedy space center at Cape Canavral in FL. Firstly, the tour bus around teh center uses the mac stratup bong (powermac i think) to alert riders to look at sights. Also in trhe 'Robot Scouts' Exhibition the woman programming the robots is clearly using an AEKII.
Now on to Disney (negatitive comment removed before written), at the MGM studios in the animation exhibit & tour you could look over where the artists do work on various computer equipment. Only 1 PowerMac was visible from my posistion and a monitor 17" or greater was set to 640x480. Clearly this is not heavily used cause no one in their right mind puts any monitor over 15" in that resoultion.