You were doing so well...
I was completely with you on this (it echoes my own experience over the years) - and then you let yourself down with the licence issue.
There's not much you could have done about your host forgetting the session was happening, there's not much you could have done about no room being booked, but you could have done something about the licences.
After a very similar experience early in my career I always confirmed all of the session details with my host beforehand in writing/email. This always included confirming the requirement for everybody to have their own terminal* or PC with a copy of the software on it. That leaves them with no wriggle room to blame you.
*I am old enough to have trained people in the use of software running on a mainframe and accessed by a dumb terminal.
Biting the hand that feeds IT
