how about........
the club supplys the tranny crystal... to activate your tranny and turn on the display you REMOVE the crystal and insert in your tranny.
but.. it will work, till someone drives off with it, breaks the crystal and causes someone else to crash next flight, or a newbie turns up with his crystal.

but... what about adding a frequency checker to your display to show any frequency problems, took me about 3 seconds to work out what you had and how to make one very cheap, so you need to add sommit else, a frequency checker is the perfect add on