The argument you're likely to get is something along the lines of "just because the rules don't stop everybody, that's not an argument not to have the rules."

The argument you're likely to get is something along the lines of "just because the rules don't stop everybody, that's not an argument not to have the rules." But you're right. In this case it won't do much. But it justifies the salary of many bureaucrats. They can play whack-a-mole and no one will think too hard about it, because hey it's hardened criminals they're going after right? The 'moles' will simply scatter elsewhere and those arguing to whack the moles will always have the moral upperhand, so the salaries of the mole whackers will always be secure.