These things are well known by long-time grapplers. There are safe and dangerous ways to choke someone and when you know some of them pretty well, you can tell when it's "enough". You don't even have to cause them to pass out in practice.
What prompted the original question from me was watching a BJJ grading that my friend was taking. To them, applying a choke and tapping out is not a big deal. It's no more scary or stressful than our nikkyo pin. They always tap and the person applying the move always releases immediately.
After the tests were over, the teacher doing the testing awarded the new belts and ceremonially choked/strangled each person with their new belt while they were standing up. It looked a bit freaky, but they were all explicitly instructed to tap when they started to feel it. Some of the guys let it go a tiny bit too long before tapping - they had to shake themselves awake a little bit afterwards.
It looked pretty safe and effective the way they were practicing it.