Um, removing a person who’s giving a talk is a completely different action from the distribution of (potentially) unlicensed software.

DEFCON may well have many reasons and legal recourses to stop a talk from occurring. But if they do not meet the terms of the contract for the IP, then the author/developer/manufacturer is entirely free to pursue action against them.

Now it’s possible the developers had not watched Mike Monteiro’s “fuck you pay me” talk (https://creativemornings.com/talks/mike-monteiro--2/1), but assuming that the claims in this tweet are remotely accurate you can bet that - assuming they can get someone to do it at all - next years defcon badge will be produce by someone with a contract that has the only sane language: “no transfer of any IP or right to distribute occurs until receipt of full payment”