I had to sit quietly with my hands in my lap and listen to the sermon. It drove me nuts. Since I don't carry a paper Bible when I've got QuickVerse on my laptop I couldn't even follow the sermon. Fortunately my wife had pity on me and shared her pocket NASB with me. The itty bitty print wasn't much better than nothing, but it did the job.
Portable devices run on batteries, and batteries die.
If you're using a Palm device you're relatively immune, since batteries last so long on a Palm. But you're actually more likely to be catastrophically shut down since you probably don't carry a pocket full of AAA's. After my power disaster I located all the outlets in the auditorium and always made sure to sit by one, and to carry my power supply with me. I resorted to plugging the unit in on probably three or four occassions. The best outlets are those recessed ones in the floor.