How do I avoid looking and acting American while traveling in Europe?

Unfortunately, I drew the short straw and will be heading to Europe on
a business trip this summer. Now my primary concern is just making
sure I get through this trip and back to the US safely in one piece.
I figure this will be a challenging task with all the reports of
anti-American protests and assaults on American tourists.

That said I'm trying to compile a list of tactics that will prevent me
from being a target:

1. Never dress casual - I figure most Americans can be spotted a mile
away by something "wrong" with their wardrobe. Tailored English suit
should help keep me out of trouble.
2. No shouting or raised voices - Always speak at a level tone
3. Show no emotion – No laughing, no smiling, no signs of frustration
or desperation.
4. Do not leave the hotel except for business – When the business
meetings are over, head straight back to the hotel and stay there.
5. No American greetings – "Hey", "Hi", "Howdy" and "Yo" are banned.
6. No hand gestures when talking – especially no pointing
7. Walk upright; do not flail arms too wildly when walking.
8. "Bob's Your Uncle" – Rumor has it that this phrase will stop an on
coming mob of hooligans in their tracks but I haven't confirmed this?
9. Correct words - "petrol" instead of "gas" or "fag" instead of
"cigarrette"
10. Little Canadian flag lapel pin - Last resort, but I think the
Europeans would just assume I'm an American trying to fool them with a
little Canadian flag pin.

Any other suggestions?