Frequency control at your club
Additional frequency control suggestion:
If feasible- put a sign at the entrance to your flying field instructing that radios are not to be turned on unless you have the frequency pin, or words to that effect.
Reason for this suggestion is that I once lost an airplane when a person totally new to the hobby showed up at the field and as he exited the car flipped on his transmitter. Unfortunately he was on the same frequency as I and my airplane drilled a hole in the ground. This person was a young teenager, and had no concept of frequency control. Parents had bought him a complete setup- radio, engine, arf plane, etc.