That's what I'm wondering, if it's a Florida thing, or just these two local tracks, or if they are starting to crack down widespread.
I just did some checking on the Z06 forum. Several people complained about the rules and having to drive under them. The tracks let them run unless they run quicker than 11.49. Then they get the boot and have to wait a month or so to come back. They all seem to be in the southeast. But there's still people running low 11's with no cage or driveshaft loops at some tracks elsewhere.
If I have to put a cage, 5 point harnesses, a fire jacket in the Florida heat, a blanket, and a driveshaft loop into the car, that really would stop me from buying it.
When I ran my 11.501 in the C5 Z06, the NHRA official pulled me aside and told me to ease up. He then told me all this stuff that I should have if I didn't. Next run was an 11.85, I got the message.