You know CF, I think your invitation to Rich B was tongue in cheek, but I have first hand experience that a true fan can never change allegience......
I guess it was early 80's and both Forest & Leicester were in the top flight. I come from Melton which is equidistant from both cities, but being in Leicestershire, most of the Melton lads were LCFC supporters. We were losing almost every game and were bottom of the table, while Forest were winning every game and in the top three.
A mate from work was a Forest fan and knowing I went to City every Saturday, he asked if "I wanted to see some REAL football, and invited me to take the spare ticket going for a Wednesday night game, Forest v Ipswich.
Forest played some fantastic, flowing football that night (this was around 1984) and rolled over the opposition 4-0, but you know what.......... I didn't feel the remotest flutter of emotion or joy.
That night I knew deep in my soul that I was "Leicester till I die" regardless of the awful football we had to stomach & the frequest losses we had to endure. I never went to another Forest game after that, and was deeply ashamed that I had cheated & had a sneaky "one-night-stand" on my beloved LCFC.
So, Rich B and his fellow Forest unwashed, are currently going through a living nightmare that's lasting an entire season, but he/they will be back next season (even in Div 1), because that is the 'lot' of a true British football fan.