Sometimes with collaborations like these, there's a leak. When the leak makes it to the press, then the press calls up the collaboration.

If the spokesman for the collaboration can't say, "Nope, we haven't seen anything interesting. It's all boring, please go home.", then the journalists know that something's up and the hoopla starts.

Scientists like to talk. It's our job. Collaborations are only partially optimized to contain leaks. I sincerely doubt that any part of the rover team would like to stir up hoopla when they aren't certain about results.