There's only one thing Rick and co can do - fight. The Governor is going to attempt to exterminate them whether they hand over Michonne or not. So why send her to a very long and enduring death (if he even lets her get to that point) knowing the Governor plans to pick them all off one by one, anyway? Better to keep her with them to help fend off the impending Woodbury attacks than to hand her over and be one fighter down.
The planned meeting time would be an excellent time for a little woodbury terrorizing. With out the Guv in town you think you would be able to distract the gaurds at the front gate and pop a hole or two into the side or back end defenses of the city. The Irony is even though Rick does not know, we know alot of people will be ou tof WB at the time, making an even better oppurtinity for attack.
I guess in my logic, If I were Rick i would want to anger the Guv and get him to attack me on my ground. The prison is well defendable. It is the waiting that will start to deplete resources. The Hard part would be getting back to the prison before the Guv attacks. I would assume the Guv would have to fall back to refortify and gather his remaing troops before his attack, but who knows.
I like this idea in theory, but I don't know if I see the Governor actually going to that meeting place as stated, not even if it's just to kill them all and grab Michonne. When he was telling Martinez to kill the others and keep Michonne alive, I got the feeling that he's sending them to do the dirty work but doesn't necessarily plan on going. Why should he? It's not like he's actually planning on sticking to his end of the deal. He's also probably smart enough to know that if the group rejects his deal, that it would be the perfect opportunity to plan an attack on Woodbury.
Imagine Rick showing up with Michonne, asking for the Governor, and being told he isn't there. Someone grabs Michonne, Rick realizes he was set up and most of the stronger members of the group are with him (Daryl, Michonne, possibly Merle since he doesn't seem to like Daryl going off without him). Who's left to defend the prison? Carol, Hershel, Maggie, and Glenn. I'd be surprised if the Governor does actually go to meet Rick himself this time around.
I agree with luring the Governor to the prison...provided they have defences in place. There are too many holes to get into, but that can be useful to set up tramps and such things. They attacked once and got out in one piece, they could probably do it again but the challenge would be more getting into Woodbury than getting out, this time.