With all due respect my friend, I would have to disagree-- a compass error will and does cause erratic behavior in the Phantom and a recalibration of the compass almost assuredly resolves the issue. It has happened to me 3 separate times and in each case, the issue was resolved with a compass recalibration. So to assume that it is a "ritual" is not correct IMHO.If you are within 100 miles of home you shouldn't need to worry about recalibrating.
The usual cause of a compass error is trying to launch from a car roof, manhole cover or concrete with steel reinforcing.
In those situations, moving the Phantom to a clear launch point is all you need.
Trying to calibrate for the magnetic effect of a bad launch point won't help you fly up in the sky away from that point.
Pilots of full scale aircraft also go through many "rituals" or checklists before, taking off to avert problems. Pilots of Phantoms should use checklists and a part of that check list is compass integrity. When followed, this may also prevent a crash or fly away.