I agree that spotters are becoming VERY important now. Our field has a large group of imac flyers and it has been a struggle to get along with them hovering directly on front of the runway center with no concern for patterns. Two years ago i was flying my AD F-16 when an imac plane abruptly pulled vertical right as i was making a fast pass.I drove right thru his horz stab and took it off like a saw. He went in and i finished my flight, landed with some splits here and there on the fuse.The guy was not happy and we almost had a fight.This past march i had a midair with my new roo with the same group of guys. The flight stations at our field are spread far apart and its tough to talk to another flyer. My spotters are now VERY important and i also try not to fly when the imac guys are in the air or come out and fly during the week when its not busy.
Our jet 3D stuff is not like the imac flying where they hang on the prop and do tork rolls forever going up and down like a yo yo.