HTH
There are many ways an aircraft could enter C accidentally beyond just a nav error.
I think here we have established that to make E work transponders need checking, which comes back to the main point we agree about, being on the right freq, ie
"Brisbane Center, XXX, 120 GPS on 150 Radial Cairns, 6500, squarking 1200, Morning Plazbot can I get a transponder check please"
Oh and lots more education, a failure of the NASIG that AOPA is trying to address.
AK
PS, one day Plazbot I'll tell you my rego and we can wink at each other
I mean, if I can do it so can others within your organisation. Use different computers!!!