when aohige say so, you bow and thanks
If you think the conqueror haki is under used think this
they call a buster call, you shout your haki them will be left only the VA and
a few captains,
Ray-san most likely calibrate his haki otherwise camie and nami would faint
Shanks faint dozens of WB man, the only showm ok were the captain
I think it`s not something that would give You the edge in a battle
but it's related with the person ability to surpass dificults and luffy case
to make friends by the respect he conquer.
The foam it self is like aohige said, you can see thousand of people
that faint by haki without and thousand that faint by other causes with
so we can not use dis as hint to predict if haki were or not used
http://read.mangashare.com/One-Piece...4/page005.html shanks faint and foaming evybody
http://read.mangashare.com/One-Piece...3/page018.html some foam other not, like that