Ehab and Philo said it all.
Maybe RCPete is trying to make an option available to someone who does not know anyone at a jet meet.
What if you walk up to the least qualified flyer at the jet meet?? Say someone like me!

What if you asked him to spot for you and the itsy bitsy spider tries to 86 your eyeball. Now you've got someone who you don't know who is flying your pride and joy

.
Dicey huh?
If I haven't seen anyone fly at a jet event then, I'm not too keen on asking them to spot for me. Do I go to the guy flying the 60% f-14 with all the bells and whistles to help me spot my A-10x? Probably not.
RCPete's idea maybe helpful in the first few flights of the day when You are just getting to know people. This spotter should be a competent RC Jet pilot who has flown at least 2 different kinds of sport jets and scale jets and is a nice person. Maybe being nice should be the first requirement!
Sorry to blab on....
Raf