Threatening Mythbusters is probably a matter of 15 billable minutes of legal time. Whereas building a secure RFID is hundreds or thousands of engineering hours.

Here's something that just occurred to me: One reason why actual security is more expensive than lawyers is that your security team is up against black-hat hackers who are willing to spend hundreds of hours working -- anonymously, in secret, and without pay -- to defeat you. Whereas your legal team is generally not opposed by a black-hat legal team that is willing to spend hundreds of pro bono legal hours to try to defeat you in court. Particularly because you can't challenge a legal threat while simultaneously remaining anonymous and working in secret.

Building the insecure RFID is also hundreds or thousands of engineering hours. There is a lot of grunt work that was done regardless; designing the radios, designing the manufacturing process for the ID chips to be as cheap as possible, etc. Getting the crypto right isn't much on top of that.