What would happen if one pushed, shoved or kicked a guard of the Unknown Soldier Tomb?

Well, on the occasion that it were relevant on me, you would pocket a bayonet to the eye socket, but since our soldiers are the most disciplined in the world, probably you would just get arrested.
But this is a non-issue. Do you really cerebrate they would even criticism you and your wimpy kick or shove. they would probably just think you were an insect pestering them.
Oh yea, precise and likely scenario - almost probably, the veterans who were partial there paying their respects to their fallen comrades would take you out behind schedule a large tree also teach you some manners.