Alrighty, I'll give it a -1, here's why.
You say that it's been turned into a non-productive waste of time, but what was it before? Not sure about you, but I remember CT's just sitting in a CT only room for 8 1/2 minutes before the change happened. If that didn't happen, it was honestly just a rebellion on 20+ T's vs 10 - 12 CT's. I've played both sides, neither was fun. T was too easy, CT was boring just shooting people.
Next, you say a freeday where T's can't rebel is a waste of time. From that, it seems to me like you think a freeday is SUPPOSED to be for T's to rebel, (Which is fine) but when I think of a freeday, I think of it as a little break from both sides just shooting each other and just... chilling? It usually doesn't go that way but when it does, it's pretty cool. I can remember towers of players alternating to reach the top of the map, just to have fun. And this is the thing, while rebelling can be fun, I honestly find it more interesting to play games. Honestly, when i'm playing surf or climb or some other game and I mess up late, I get scared, and I LOVE IT. It's fun and exciting at the same time. I get it, a lot of other may people may think I sound like a tame little child right now, but hey, I find it fun. The point i'm trying to get across is that the point of JB is to have fun, not just win rounds. A freeday gives new players the chance to have fun, and learn the map, the old freeday doesn't.
Lastly, you say this gives cancer wardens the ability to delay. This goes back to JB 1.0 special days. My praise and thank you's go to the angel(s) who decided to remove HG. People would do HG just to increase a number on a scoreboard, and for easy kills. With the freeday, that can't really be done. If someone is that desperate to waste time they're honestly better off just getting off the server and doing something productive. Not sure where I stand on that point actually.
Anyways, I like the suggestion, but still a -1 from me.