Inexpensive and SO Quick and Easy to use... :)
Attachment 142043
Have several on hand with universal balance boards on them... Have several people appointed to do checks. Maybe have some kind of tech sticker or card that signifies tech as been done.
Voltage Problem solved.
I'd only do this at MAJOR events, however, where the stakes actually count for something (well, do they ever REALLY count for something, in the big picture?? :) )