Pretty sure you have to be notified of and agree to a rest period prior to said rest beginning. Waking up one day and seeing that you've been on a 30 hour rest period without your acknowledgement isn't legal. That said, you'd better be darn sure you didn't click through something on iCrew or MiCrew without thinking and acknowledge a rest.

As a data point, the only contact I've had from the company since March has been phone calls periodically notifying me of 30 hour rest periods. It's always been a phone call. Never an icrew popup and I haven't used MiCrew in weeks since it started lagging significantly on schedule/open time changes.