Given the well documented gap between what Google reps say in interview (sometimes off the top of their head) then what Google publishes in official guidance, and then what Google actually DOES in practice I no longer consider MC or JM remarks a more reliable source than any other. Worth considering, yes, but not the final word.
The example on Google's link scheme page quoted by linkbuildr refers to "Links with optimized anchor text in articles or press releases".
Press releases were around before Google, and if they are still used as they were always supposed to be used (i.e. NOT as a means to syndicate an anchor text link within some non-news) I'd be surprised if they could cause harm.
Just like not all directories are bad, not all link exchanges are bad, not all article sites or blogs or forums or anything else is bad, I personally would bet that not all press releases are bad.