Certain professions naturally require employees to be called out...

Certain professions naturally require employees to be called out from time to time.
If an employer has an expectation to be able to call employees out after hours, simple, pay an oncall allowance!
In my employment, particularly when remote, we were expected to be "on call" 24hrs a day, and as the applicable EBA stated, had to be "reasonably available".
When asked they could not define "reasonably available"!!!
It was common for us to be called out multiple times a night, with no oncall allowance, that has now been rectified!