First and foremost, I hope she returns home safely and quickly this time, too.

When I poofed Churchy, he had been raised from kittenhood as an outside cat. His vet said one of the hardest things to do is convert him to strictly indoors. I was a bit surprised that it wasn't all that hard, he howled by the doors and windows for a few weeks, stalked us as we were leaving or coming back in, and his behavior was horrible. We stuck it out and now he's a healthy, happy and safe couch cat, lol.
Of course she's going to howl, she's wants outside, but the simple fact is, she's put herself in danger and now precautions need to be taken for her own safety because you obviously can't leave it up to her.

You ask if it's fair... yet she's the one with the infractions on her little record. You have to think of like you're trying to keep her safe. She's been trapped in an unknown location, and even though she faired well last time, this or next time she might not. Keeping her contained, whether inside or outside, is fair because it will keep her safe.
I would be worried that my others would catch on to her actions and start a little exploring on their own.

I think she does need an outside area, totally enclosed. Make it large enough to pretty it up with flowers and maybe a tiny little pond. Put a large flat rock in a sunny corner and you might find that you'll use it for all of your cats more than you thought you ever would. Trips to the store, company coming over, remodelling in the house...I can think of a bunch of times I'd love to have one.

Good luck little Zazou...please come home!