Re: Covering Head .
Its a sign of RESPECT. Carried over form Culture. To a SIKH the KESH is very Honourable and deserves UTMOST RESPECT. Hence Kesh must be covered at all times even in the home...and by extension in the Gurdwara.
IN Punjabi Culture a Bare headed person is regarded as not "right"..a sign of GRIEF ...to a woman being bareheaded means her husband is dead...etc etc.
IN Western Culture a gentleman shows respect by REMOVING his hat and going bareheaded..in Church a hat is REMOVED and keeping it ON is a sign of Disrespect...
Gyani Jarnail Singh ji it is pretty hard to add much to the wisdom with succinctness that you share here at SPN.
If I may be guilty of an indiscretion I will like to add an additional aspect for head covering.
Specially for female members of the congregation, in practical terms it is also an expression of modesty. If a "chunni" is employed by a female, it provides partial coverage to the jewelry one may be wearing (minimum or none is encouraged in Sikh Rehat Maryada) and lower arms. I know when we were very young our aunt used to use part of her chunni to cover our head too as we will snuggle up to her and as needed.
Regards.
Sat Sri Akal.