A SaaS startup I used to work for tried to implement on-call rotations for their salaried engineers. No additional compensation was offered for the time you were on-call, and if you did get called, the policy was going to be essentially “take the next day off” - when we already had unlimited PTO. I was not happy, and made it known at the time. My manager mentioned that, being in a senior role, I might have the opportunity to excuse myself from the rotations. Ew.

The effort didn’t end up going anywhere, but that’s been my sole experience so far with on-call efforts in software engineering.