I think this incentive is good. There should be a difference between trial- or unlicensed installs vs. licensed. The licensing work in progress will most likely allow privatees to license.
A correction on MS is that you can download the patches manually and install them, Only a few require authentication to actually install, and there are ways to slipstream them onto a system as well.
Regarding a mailing list, for all unlicensed, the pm-news list and this community is still and most likely always around for announcements, but the latter is mainly a pull method, whereas a list is a push system. Now, email may not reach all, depending on content, format, sender hickups, receiver policies and other hickups that arise from time to time - therefore - a phone-home system within Mercury/32 that is allowed to contact and inform of new releases, then notifying locally that information exists is a very charming way to go. A such system must though be thoroughly tested due to its importance.