I have not tried it but functionally there is probably a good reason for not allowing it if it not working that way.
In my job we have certain screens that only one person is active in those screens. One is an approval screen. If a second person is in it they could manipulate data that another person is approving it if they are not locked from that screen
My guess it could be the same here. Two people are in it and one leaves that did not start the recording then the software may think to end the recording. Or the person who was recording leaves but the recording continues as the other person is still there. It could create a ghost session where it is recording and nobody is viewing it.
There may be other limitation or reason why not to allow it.