I remember a similar experience Arand.
This was back during beta, and right after the last p-wipe of beta (i.e. - the one before the BIG wipe at release) I switched from fighting for the NC (as Draco) to fighting for the TR (as the now infamous SpaceWolf). Well, after a while, I missed my Phoenix so I went back to the NC on another server. IIRC, back in those days hotspots showed up for any fighting, unlike now where they only show up for your side fighting.
So I'm in the HART looking at the map and plotting where to go when I see some real mean fighting between the VS and the TR. Completely forgetting what side I'm on, I drop down near this fight and get out of my pod...then I wonder why all the TR names are in red and I guess I hadn't had my coffee yet that day because for some reason it struck me as normal since...after all, the TR are red. Don't ask...I still can't explain how that thought made it through.
Anyway, I'm running around shooting at barneys and really, the TR guys aren't bothering me that much. Then a Prowler blows me up and I'm like "WTF?!" and then look at the kill window and go "Ha ha! There's an NC guy here....and he's got my nam.............aw crap..."
I returned to Sanctuary completely mortified...but looking back now it's funny as hell.