[wst_]

Not sure I agree with that. It's not difficult to notice one has "nai", other don't. Also when you read it in actual sentence you can immediately notice that something is wrong when you choose the wrong reading. Subsequent words don't add up. I am not saying confusion doesn't occur. I'm just saying it's not as big as people are painting it.

[iopq]

It's not always the case it's followed by nai

大人気なくてもいい means it's okay to be childish