Never tried it, but my guess would be no. Not sure why, just a hunch. It's easy to test though. Just take the includes out of the kids and fire that pig up. See if it goes ka-blooey...if it doesn't, then the connection must have propogated down.
I'm entirely too lazy, but it stands to reason that you should be able to test it pretty simply. If you create a frameset and populate a vbscript variable, then if it DOES propogate, you'd be able to see it on the kids right? So create a vbscript variable on a parent and try to reference it from a kid. Now you've got me curious.