While your approach is definitely the safest way to go, I think that it really is, as has been expressed here, more of a 'local' phenonema. Especially as regards 'touching' a policeman!
The U.S. in PARTICULAR seems to accept this attitude by a policeman (that he's OK to shoot first and ask questions later). Maybe it's because concealed weapons can be carried by anyone. I don't know.
But I can tell you that I have tapped a cop on the shoulder, here in Toronto, and all he did was to turn around, look at me, and say 'yes sir. How can I help you".
I also know that I would never tap a U.S. cop on the shoulder, simply because all that I have seen look more like a weapons mart on legs rather than a person out there to help and protect me!

cheers


>I think the smart person, in any society, never touches anyone who carries a weapon and knows how to use it. That is just common sense... why would you need to touch him/her anyway? To many people (let alone those that are accustomed to being verbally and physically attacked by those they serve) touching is an invasion of private space.