Not sure about pushing, not being seen, if that is the case then all strikes should be concealed similar like a push, the one who is pushing will think they can get away with it??? Not! No contact... It is battery on ones person, pure and simple.
It is an attack and should not be condoned. If you are that close to a person, then you have entered their space or they have entered yours...Don't allow that to happen...
If you are in an elevator/subway train, it is one thing I guess and pushing happens
Link to Law:
A taste of the link:
A battery is the willful or intentional touching of a person against that persons will by another person, or by an object or substance put in motion by that other person. Please note that an offensive touching can constitute a battery even if it does not cause injury, and could not reasonably be expected to cause injury. A defendant who emphatically pokes the plaintiff in the chest with his index finger to emphasize a point may be culpable for battery (although the damages award that results may well be nominal). A defendant who spits on a plaintiff, even though there is little chance that the spitting will cause any injury other than to the plaintiff's dignity, has committed a battery.