FYI if your employer does this, if they have done it for a long time especially, you and your coworkers could be owed huge amounts of unpaid wages and it would be an easy suit if there is a paper trail like this and your employer is placing strict requirements on your behavior while not at work. Employment lawyers generally work on contingency. Just food for thought.
A national park I worked at had all the permanent rangers (I was seasonal) basically on stand by for call outs 24-7 or they were penalized on their reviews.
They got tired of it, sued, won, and the nps had to pay back YEARS of back wages for stand by time. Now they are all scheduled and if* you get called out its time and a half.
ONLY because some rangers stood up.
If your employer does this: document document document, then find an attorney
