For the record, I was still looking at TC/MC 2.2 as those were the last updates I did on my Aspire One and I didn't have my USB stick with me today (I'm not inclined to update since I rarely even boot into Linux on it anymore and only use wifi when I have my USB adapter due to ath5k+WPA timeout issues; this all arose on another computer). I was looking for the simplest possible solution which could be handled at boot and through reboot without remastering or setting up tweaked files via filetool, etc.
I think I like your approach even though I think I'd prefer to leave ownership to root(.staff) rather than user. Or a separate tty group, as some (not all) distros do. I realize the possible gains in security are negated by wide-open default sudo privileges, which is one of the concessions which is necessary for a nomadic environment. Nearly everything is owned by user tc and/or group staff and tc can sudo everything without a password to do anything tc.staff can't do.
In any event, perhaps Robert and Co will either edit /root/.profile as you did or edit udev rules accordingly/appropriately.
PS: Added props to maro on my blog entry (last link: microcore and gnu screen fix).