It's interesting that both the article and many comments take as a base assumption that on-call should exist and then go into how it should be compensated or structured.

I would argue that on-call shouldn't exist at all. If a company wants a system to be supported 24/7 it should have three eight hour shifts. Of course companies balk at this, saying it's too expensive, but if their product isn't worth paying extra for then perhaps it's also not worth being up 24/7.

This is the sort of thing that should be enforced by law or by a strong union contract because businesses can't be trusted to act in their employees' best interests.