I think they would've sat on it for a while, yes. I support them for it. When the great observatories of the world make fascinating discoveries, you don't hear about it that day!
Most scientists are not forced to do instant analysis on their data. The way science usually works is you get your data and you have TIME to analyze it before making announcements about what you've found. You publish in a professional journal refereed by your peers -- people qualified and experienced enough to make a thorough judgement whether your research has merit. Yes, that's the ideal case, but it really does mostly work that way.
You must admit it's easier to look at raw Cassini imaging data and type, "Eureka! I've spotted so and so..." on your blog than to stare at a MER microscopic imager photo and know what you're seeing. Even more the case with non-imaging data. I can't decipher mini-TES data, maybe you can.
So again, the way science *usually* works, you take the data = you get first crack at it. Knowing that, can you blame someone for getting ruffled that their data are on display? Yes, the scientific culture is hierarchical and sometimes stuffy and even closed-minded. But it works pretty darned well.
And PR is the other side. There's a term in the news business for when someone else publishes your story before you do. Getting scooped. It applies in science as well. And when you miss the boat, it's gone. When a story breaks, the media don't wait for you to get ready. If the story's hot, they publish it. And if it gets posted to the web first by savvy amateurs, they will still publish it. So like I said, I for one do not blame the imaging people if they make the public wait a few extra days (or even a few weeks, months) to get their story straight and make a big splash. They've earned the right with their hard work. I don't see the need to get all indignant about want to peek over their shoulders 'cause you paid for it with your taxes.