Formation flying as though you're in a Vic over the Channel in the Battle of Britain or on a magazine photoshoot has got to a dangerous pastime unless you're well trained.
IMHO flying withing 25 metres of another aircraft is undesirable because of the small margin for errror. Say one guy avoids traffic by turning left. The other chap is checking his chart or avoiding a large seagull. Oops, you're dead...
But I don't see the problem with flying in company with set parameters eg two pilots in each aircraft so that the handling pilot can concentrate on handling while the other pilot does the nav/radio. It happens in Club Fly-outs all the time and is probably safer than having 10 aircraft converging on the same destination without any coordination!
And compared with flying the circuit at most training airfields where you regularly have 3 students or low hour PPL aircraft at various speeds and altitudes on each leg, not to mention the fancy-dan CPL students joining left base in twins, it's a doddle.
