in the philippines, we touch the hands of our 'elder' to our forehead. i know the bowing thing is foreign to many in the west, so i try to distill it into its simplest form
bowing in the east is a form of greeting and respect:
in the east we bow
in the west we shake hands
all over the world, dogs sniff butts.
i try not make too much out of it.
...Sometimes I wonder, if Aikido originated in a culture were the form of respect was to kiss the hand of forehead of your Sensei, would everyone worldwide be expected to do it?...
my feeling is if its a japanese art, then japanese etiquette is followed. that's why we wear dogi and hakama in practice, and that's why all the techniques we learn are in japanese.