Emergency is they key word here that will be abused by those that have an issue with this rule.

If I'm at work and receive a call that my partner/child/family member was in a car accident, that's an emergency. It is a rational and reasonable expectation that work understands I need a day or two (or more) to address this emergency.

Similarly if I'm at home and something with our widget affects a human life, that's an emergency. But it's also a one time emergency. If we produce widgets that result in emergencies then the next step is to hire/pay employees to cover widget emergencies.

As an invested employee I want the company to succeed. However if all I see is emergency after emergency. Failure to address emergencies. Or even false emergencies. Well then fuck off.

Employees have traditionally given a lot of slack in this area. Abuse by employers are what have caused these more official rulings.