I don't know what browser you use, but I'm not familiar with any that both allow notification requests and don't allow you to turn them off somewhere in settings.
I’ve noticed sites putting up a fake notification modal first, and then triggering the real browser pop up only if you click yes. I believe this is so they can ask you again on your next visit if you say no, which you can’t do if you deny the browser pop up.
You can thank OneSignal (YC '11) for that.
I was gonna write that notification modal without user interaction will be deprecated. But I guess that will not help then.
Mobile apps have been doing this with permissions dialogues for ages.
Fool me once, shame on you. Fool me twice? Not going to happen because JS got disabled for the site the first time around. Site doesn't work after that? Too bad. It's not like there aren't a bajillion alternatives.