If I'm flying with a student, then they are 'under' my RT licence, same for a solo student. Once you are no longer a 'student' you need your own licence. As a non-FI cannot 'instruct' then strictly speaking they cannot have somebody 'under' their RT licence.
It would be very hard to prove who spoke on the radio however unless it is recorded.
Given the standard of most RT it doesn't seem to matter if you have the certificate or not, it's invariably awful!! "G errr ABCD err umm inside leg measurement etc..........."
David, I can't agree with your comments. If we didn't question how and why we do certain things, then flying will remain static. How on earth could the CAA or whoever tell who handled the controls at a certain point?
Traction engines are big, noisy, dangerous things and I am in no way surprised that they may have to be fenced off. With all the whirling cogs, pistons and other small curious children mashers I'm amazed it hasn't been done already. If the Steam people had taken the lead in this sort of thing, maybe the HSE wouldn't be so draconian.
The only thing that can beat a beauracracy is to try and pre-empt them and any concerns they may have. If you can prove that you are doing everything possible they'll leave you alone. Look at the PFA for example, they took a 'sport' with a dreadful safety record and changed peoples thinking and took the lead. Look what a great organisation it is now without the Belgrano butting in every ten minutes.
Compare this to the contrasting fortunes of the gyro-copter brigade and you'll see how to do it and how not to.