Would the Code of Hermes permit the erection of a "Consensual Scrying hut" on covenant grounds that can be targeted by "summoning the distant image" (Arm5, InIm25), cast with no penetration. The door of the hut would inform the person who enters that this room is used for magical communication.
It would allow magi in the field to report back home (if they have an arcane connection to the hut) and magi in the room to answer (if they had an arcane connection to a magus' grog in the field).
It would be the invention of the cell phone (well it would require an Astronomy roll for larger distances to determine calling time - right time zone, or a spell that reports scrying).
Look at Haunt of the Living Ghost, ArM5 p.144. It clearly explains that if the person you are talking to can see you, or presumably knows you are doing it, it does not count as magical scrying.
And I'm afraid it also means you are reinventing, not inventing, the cellphone - it's already been done
"I will not use magic to scry upon members... nor... to peer into their affairs."
So, by a pure reading of the Code, there is no "consent" that can circumvent this prohibition. With permission, without it, it's still scrying, it's still peering.
However, I doubt many Tribunals would look kindly on a case brought by a mage who first gave permission and then complained about it.
I agree scrying is scrying. Consensual scrying is still technically illegal but if the target doesn't complain (because it was consensual) then there is no Tribunal case to answer.
As Cuchulainshound says, complaining about something that you have consented to, is likely to be frowned on by the Tribunal. On the other hand, consent would not be a clear defense in all cases --- if the target could prove that they consented under duress or that they were Mentem muddled into consenting (or believing that they had consented), you would have a problem.
