Conrod
We had the same thing happen in our club, even with a pegboard some twit is always going to forget no matter what rules warnings etc. Our club now has a members list with everyones frequency on it. There are NO double ups and every new member is given the list and told to buy gear on a different frequency. We still use the frequency board ( to ensure we keep a routine for visits to other clubs, Visitors etc ) but it is always nice to know that you can concentrate on flying rather than what others are doing in the pits.
Being in NZ there is no reason you should not be able to buy a set of crystals on a different frequency and chance them out. I specifically picked a set that has limited numbers of users in NZ. NZMAA have just completed a frequency usage table, use it to your advantage.
Its not going to bring back this plane but may prevent/slow the loosing of another.
Best Regards Steve