All stations share their EAS infrastructure. The largest stations get their data direct; smaller stations get it from larger ones. All stations need to have at least two different data sources set up. It is actually a reasonably well set up topology, and it is tested on a very regular basis.
The FCC also imposes strict fines on anyone who fails a test; the base fine for a violation is $8,000 and is scaled up for repeat or blatant violations.
How the FCC handles fines in this case will be interesting. The EAS system is designed for speed and reliability, not for security; there is message validation built in to prevent unintentional activation, but a correctly-formatted bogus message inserted into the system will propogate as designed.