I won't get into specifics, because I only have a tiny sliver of knowledge when it comes to Disney Security. And, I only know that stuff as it related to one of my previous Disney roles. But, I can say that the security you see at Disney World/
Disneyland isn't the only security.
Example: Back in 2015, Disney made news by posting a job opening for a "Global Intelligence Analyst Intern" in order to compile a threat assessments for "counterterrorism, physical threats, cyberattacks and all reputational risks" to the company. That wasn't the type of PR the company wanted, so the job quickly disappeared. But, I have no doubt that Disney still does those types of things. They just recruit for those positions in a less public arena.
Source:
https://www.newsweek.com/disney-looking-counterterrorism-intern-384347
As for enforcing a ban, the biometrics isn't designed to accomplish that task. There are other systems and protocols to help identify those people.