I'm still running the Windows 7 RC1, and found a neat feature that might mess with the Platform. Following some updates, it will automatically restart. Now, it does tell you (and gives you a 15 minute countdown) but it's easy to miss if you get sidetracked. And once the counter gets to zero, it simply automatically reboots, seemingly without any consideration to what you are doing.
Won't this interfere with portable apps and the Platform, since upon exit, the launchers are supposed to perform cleanup operations? They won't do that if they're forced to close, will they?
I assume that at some point, Microsoft will give developers some level of access to that API so they can make their applications react to it. I don't follow that stuff, so maybe they already have.
Either way, IANAP but if the Platform can somehow monitor that process - since it's on a 15 minute countdown, a quick check every 10 minutes will mean the Platform has at least 5 minutes to react. The platform should then call separate attention to the user and present options. It could offer to close the platform, all portable apps (though that wouldn't apply to non-PAF portable apps, e.g. CCleaner without the launcher, but those apps probably don't have upon-shutdown actions), or to do nothing and let the user close them down on their own; however with a set amount of time to spare (30 seconds enough?) they should all close down automatically, to preserve portability.
Just a thought.