Ooo, er, missus!!
Are we now saying that turning it ON will take two or three sweeps of radar to acknowledge that it is there...but turning it OFF is instant lack of data?
Looking back through the messages it seems that TCAS is the thing we are trying to protect...rather than ATC confusion.
I was surprised to see mention of "code change" on handover...I would have thought (although, presumably, incorrectly) that at the levels where heavy metal meets PA28...all code changes would be finished and the little guy (me...hence the reference to teaching students) would already be identified and locked into the airspace system that the heavy metal deems to be theirs (and only theirs).
On the question of "Will I still teach that way?"...to be honest, I don't know. I'll probably - as I do with many aviation thingies - show 'Gromit' (I don't fly with Bloggs anymore) both ways, discuss the comments and options and let him/her suit himself/herself in the future. Whatever I tell him/her...I may be wrong.
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LIVE in peace...or REST in it!