Psikerlord#
Explorer
I don't use passive at all. I just allow auto succeed or else roll.
The problem with the original scenario and how it plays out is that the more rolls you demand, the more likely the d20 fate gods are going to have a bad roll come up. It normally only takes a single bad stealth roll to take things south.
In early levels, you have a stealth mod of +5 to +7 or so. In medium level ranges, for rogues/bards, you can expect something like a +8-10 stealth mod, for other classes, it often drops to around a +7-ish. If you have characters with passive perceptions of 15, then you end up with 25-40% chance of failing a roll. If you require several successful rolls, you are going to fail a lot. The same problem happens with larger groups.
Oh, you're thinking that passive perception sets a floor on perception rolls? No, I'm going to go with PHB 177 on that instead. Passive perception applies "even if they aren't searching," which I read to mean "whenever they're not searching."
I see that you read Mearls as saying something different, but in any case, I'm not going with that interpretation. Active and passive are mutually exclusive as I read it.