When it comes to money, that is a rather important 'detail'. Especially given the fact that the most prevalent form of theft is wage theft: https://www.gq.com/story/wage-theft
For the purposes of the article, that's still a business concern. Presumably on-call expectations are part of the compensation agreement. (as they are with most industries)
I can't think of a single job/interview/offer where the expectations or the compensation for on call were discussed formally, let alone agreed.
The best I get in job interviews is usually a mention that there is a rota every X period. Then have to poke interviewers trying to guess what is it like without coming up as too negative, "when is the last time you worked on a week end?" "when is the last time you were awaken in the middle of the night?"
The article did not mention anything about pay or compensation for oncall.