I've not met many that have switched alliegance, I do know of many who have come into the game to support it as a fan on the terrace who have been from traditional areas of Leeds where Hunslet and Bramley used to get their support base from. Instead of choosing to go to the small local club, they have been attracted to go watch Leeds instead.
That repeats across the north and may explain why championship crowds continue to decline.
As for "errors of their ways" nobody makes an "error" by choosing who they want to support. There are of course plenty on here who would pass laws to prevent anyone watching any club other than their local one.
Anyone who changes allegiance to an arch rival, was never really a fan of the club they swapped from