Seems that this thread has grown wings "pun intended" the beauty of PPRUNE.
I appreciate all the comments but the only reason I asked was to find out if it was a common practise I had never came across it before and as most people here seem to agree it is more of a goodwill thing than anything else.
I suppose considering the cost of helicopter flying it stands to reason the school would need some recompense if it had a few regular no shows.
I suppose it was the fact that I was asked to sign something that rankled me slightly but then that is modern society I suppose.