Could someone explain Cisco RTU licensing method or Honor system?

My company only uses Cisco for Wireless Controllers, we have been using 2504s which are now EOS.

As you know 2504s came with 5 AP licenses (pre-loaded) and then you purchase and upload additional AP licenses as needed.

We are moving to 3504 and can't seem to understand this RTU licensing method.

I still need to still buy licenses and upload them, correct?

It seems there is a way to add APs without actually buying licenses? (Honor System), but what is stopping unhonorable people from never buying licenses ?

Please ELI5 if needed.

Thanks