Yeah, there's a lot to be said for diplomatic immunity...
I think a lot of people assume the POTUS would actually use the gun in a "situation"... Highly unlikely...
However, there's the principle of the matter... To carry just because it is your right, to say nothing of the actual "need" to do so.
"To preserve liberty, it is essential that the whole body of the people always possess arms, and be taught alike, especially when young, how to use them." -Richard Henry Lee, Virginia delegate to the Continental Congress, initiator of the Declaration of Independence, and member of the first Senate, which passed the Bill of Rights.