Why no salute by Obama

[Varmit]

Jarhead, you beat me to it (the reporting indoors bit) and you are correct. 

[W. Gray]

Yes, but I can recall a number of times that I was advised to just shake hands, sit down, and not salute.

Saluting indoors also occurs during change of command ceremonies that would occur in such places as a gym.

And, I can recall that when going out of one building to another building and there was high traffic, there was no saluting and not even a cover was required. These places, though, had to be designated by the commander.

If a building has a courtyard, such as the Pentagon, there is no cover required and no saluting is required. Out of courtesy, though, a junior member would always say "good morning, sir" to a senior member.