Good thread Davey....
I think if a player is traded to another club and that has been the choice of the club and not that of the player then us as supporters/members have no right to hold any grudges or boo them when they play us.
Now, if we pick a player at pick 1, then develop him, put years into him, build the club around him and then he leaves....yes, I do believe we have the right to hold a grudge, its our membership money that goes towards his development, his wage his lifestyle etc.... and the club.
Ottens; we looked after that guy through all his injuries, including the roof fall and then through his form slumps, for what....him to leave. I will never forget Danny Frawley saying on his way out the door; Ottens must stay at Richmond, he owes the club.......Ottens left and I still and always will hold a grudge against him.
On another note, I also hold somewhat of a grudge against the club for trading Rodan, Maxfield, Hogg (believe it or not and we came out better off), Bond....and perhaps a few others....
So Yes I do think as supporters we are permitted to hold a grudge against self centered players that put themselves, money, their own glory and self importance above that of the club.