The main function of the checkpoint was to register and inform members of the Western Military Forces before entering East Berlin. Foreign tourists were also informed but not checked in the West.
The German authorities in West and East Berlin were not allowed to check any members of the Allied Military Forces in Berlin and in Germany.
The Berlin Wall is long gone, the memory is preserved by one of the Europe's most fascinating museums: the House at Checkpoint Charlie. The museum is crowded and photos are forbidden. One can spend hours in it and admire the creativity from the escapees.