Here is the lowdown on hat removal (for anyone interested!)

The "tipping" or removal of a hat is said to have originated from the same place as the military salute. Knights would lift the visor (face guard) on their helm, showing their face as a sign of respect and their empty hand as an indication they meant no harm. This tradition evolved into the modern military salute. Similarly, the removal of a helm (helmet) or other headgear indoors and as a sign of respect or reverence is said to have originated before the Dark Ages. This tradition was carried on throughout the centuries by men of arms (soldiers) and nobility, as well as their staff, servants and slaves. After the Dark Ages, manners and etiquette grew to become an essential part of everyday life and the conventions of hat etiquette became ingrained in civilized culture.

So - very relevant in todays world;-) C'mon - Free thinkers of the world unite. Don the hats as a rebelion against serfdom. Don't tug the forelock!

As to removal of hats indoors. Here are the rules from the same site (American) -

Indoors, a man should always remove his hat, (particularly in a home, church, courtroom or restaurant) except:
(1) in some public buildings or public places such as railroad stations or post offices;
(2) in the main parlor area of a saloon or general store;
(3) or while seated at the "lunch counter" of a diner or cafe;
(4) in entrance halls and corridors of office buildings, or hotels;
(5) in elevators of public or office buildings, unless a woman is present;
(6) if carrying packages, parcels or bags and both hands are occupied upon entry.
(7) If the man is an actor or performer and the hat is being worn as a part of a costume or performance.

So I was exempted by rules 2, 6 and, seeing as I always play the part of an old fart, 7!

Cheers

DtG