All companies I've worked at had (paid) on-call set up. The right to disconnect isn't incompatible with business needs and the law contemplates it. Also, nurses and doctors do it too.

Yeah that law is really about not taking advantage of low paid-by-the-hour employees vs high paid salaried.

But give people any excuse and they'll run with it.

In the UK custom has always been to require a standard opt-out to be signed as part of hiring process.