"at least one individual refused to cancel his rostered AAVA "
This sort of thing is ridiculous. The agreement states that you can do the shift if the company does not give 48 notice of cancellation (in certain circumstances).
What sort of person would have the bo***x to actually go in, with the company losing all that money. Hopefully the individual concerned is put on a "black list" by the ORO permanently. It is not rocket science!