The state doesn’t care.
Until the day they do, and take an administrative action revoking the licensing of all the ones in the "overcharging" file that you can bet they keep....
For those that don't understand how this works, the LEGISLATURE creates the laws, in this case the Penal Code prohibiting additional charges. Then the administrative agencies (AFT, CADOJ, etc) typically enforce them, often arbitrarily whenever there's "gray areas". Those administrative agencies also can typically ENFORCE or take administrative action against "violators". These agencies may also publish and distribute "opinions" to clarify (or add MORE confusion!!) what the legislature left in a hot mess... <insert analysis of "Chevron deferrence", recently disapproved by SCOTUS, here>
It's notable that THIS applicable Penal Code is the rare exception that is pretty plain English without room for "creative interpretation" (unlike MOST "gun control" laws). I'd say maybe the CADOJ told 'em that it's OK (bloody unlikely!), except that would put the administrative agency at odds with clear legislative intent.
Of course out of state transfers have NO limits, it's just the PPT transaction has the specific $ fees spelled out in black and white.
It's very dangerous business to add "because we CAN" charges and fees, both because it WILL cause customers to say "nope" when looking to buy something, and because it could result in serious legal issues should an administrative agency suddenly decide it's "easy pickin's" to say "well if they violated THIS law, who knows what others they are violating..." and starts audits or revokes licenses...
PS - I'm pretty sure the stupid lock requirements are also documented in excrutiating detail somewhere in the PC...