It's that, and more. It's also that they want to be able to rely on being able to call you in at any moments notice without any potential for excuses like "Well, it's going to take an hour to get there, because of the bus." or "I can't come in right now due to the weather on such short notice."

Quite frankly, I think the entire restaurant industry (in Canada) needs to be audited for multiple reasons. Tax evasion, disobeying the law in regards to discrimination, etc. (Canadian laws) There may be some innocent owners caught in the crossfire, but if they truly are innocent in this case; they should be fine and worry free. It's not a line of logic I like to use in many things, but in this case it really is true.