Originally Posted by AllanJ

Ground hold usually means there is some kind of delay at the destination airport.

You may still find it worthwhile to write a letter and ask for compensation if you feel the crew deceived you into volunteering to switch planes. It would be reasonable for the airline to explain that the delay to your plane was unforeseen at the moment the crew asked anybody to switch.

Travel tips:
http://members.aol.com/ajaynejr/travel.htm