What counts as "science by press conference"?

In May 2007, the Mars rover Spirit discovered silica-rich soils that suggest the possibility of microbial life on Mars. That finding has been widely publicized (see examples below). But, it has NOT been peer-reviewed, in the formal, publication sense. (Or so I'm told by colleagues who should know.) So, does it count as that evil "science by press conference"?

I personally heard about these findings in November 2007, while listening to a graduate student defend her research interests. It happens, of course, that I'm at the institution that leads the rover missions. But since I'm not a specialist, I didn't know that I was hearing "unpublished" results, and had the occasion arisen, I could have circulated the results more widely.

Then, a few weeks later, the mission PI (who is very experienced at dealing with the media) spoke about the results at a well-attended scientific meeting, the American Geophysical Union, where the media are often present. His comments were widely reported:

The BBC story
The Mars Society story

It's also true that NASA issued a press release about his talk, as did Cornell (and these press releases were widely posted on news sites around the web). But, given the frequent press coverage of AGU meetings, that's probably immaterial.

Many of the stories that appeared were written by well-known science writers. For example, a New York Times article by Kenneth Chang was reprinted widely (here, in the Portland Oregonian).

So, given all the warnings against science by press conference, how does this happen? Or does it mean (as Hilgartner 1990 suggests) that the charge of "science by press conference" is only used when someone wants to criticize another scientist, while "acceptable" popularizations are labeled as such?