granted, some cultures do more physical contact than others. (fine).
but, it is just more functional to do too little physical contact than too much.
i prefer none at all, especially from strangers.
some strangers (esp customers @ work) act like they have a moral "right" to touch me, just b/c there's nothing i could do about it. (cops are constantly on standby @ home depot. plenty of security guards. supervisors and managers. but i don't know whose side they would taken. maybe the customer's having sex with the boss.)
b/c once you touch someone, it's grey area whether the touch was in an intimate part of the body, or what intentions, or how many Newtons.
just my opinion. not a law, fact, or "proof". plenty of precious lil "people" do not believe in "keep your hands to yoruself"