It's more complicated in practice than it sounds though because before you join, you'll get a manager well-versed in giving you either non-answers or "soft" lies. For example, they'll say, "Yep, we have an on-call schedule. People go on every few weeks (probably meaning: 3-4 days every few weeks), and it gets a few pages, but isn't too bad." They'll generally refuse to get into specifics, and most people who are excited about the new opportunity, won't drill into it.
After you join, it's kind of too late. Best case you've got a team who's also willing to go to bat with you to get some fixes in, but more standard case, you'll find yourself on the wrong end of a pager without a huge amount of negotiating power unless you include the nuclear option of just getting out.