I know the area and I’ve been through the interior checkpoints many times. Dogs too are now a permanent fixture there.
You are right, but we can still some fun with the optics.
When I was a teenager we would drive down to acuna for you know what, wink-wink. Then smuggle back booze and cigarettes. We got stopped at one of the roaming checkpoints and they found our contraband and seized it, but they let us go without any charges.