I don't think they're isolated from the community. It's not uncommon for someone to drop in on them to train for a while, and that gives much of that calibration. The issue we're discussing in Aikido has more to do with lack of resistance. When rolling in BJJ, there's plenty of resistance, and that's enough "competition" to keep the approach realistic, IMO. I agree that competitions create better calibration between schools, and it's nice if some of the senior students and/or instructors in a school participate in competitions to gain this calibration, but it's not a necessary component for keeping the style realistic.I'll also add that if a school doesn't compete for the reasons above, that's a real shame. it's a very short step from this to the dilemma we are currently discussing with aikido. A school that isolates itself from the community, and avoids calibration, is creating all kinds of reasons they can't or won't demonstrate that their execution of technique actually works. Just like aikido. Could it work? At that point, who the heck could say?