I don't know if this is still an issue/bug or not but the last time that I played a ranger, waylay fail and would initiate or cause combat to begin within a couple seconds of getting the echo saying the person can see camouflage.

This is not the same with Ambush and the help file says Waylay just performs a standard Ambush. If they can see you, nothing happens.

waylay centaurguy
You wait to waylay centaurguy.


Centaurguy has arrived.
But they would be able to see you.
You stop trying to waylay your prey.


No combat started.

But if it did, I'd be fine with that too.