My bro was one of the guards.
People think of the Tomb as a tourist spot, maaaybe as a monument. They forget, it's a grave, and as such, it's entitled to be shown respect. The fact that it is a grave for the remains of soldiers that gave their lives and their identities serving our country means they are entitled to much more respect than is generally shown by the public visiting.
The Tomb Guards are a elite unit, and they take their duties very seriously.
Thank you for your service, RetiredJedi. And Airborne school is pretty awesome.