I guess you're already kind of resolved about this, but I thought I'd tell you my standing on it anyway.
If I receive messages and wall posts asking for me to join spots or 'fan' content from Fanpoppers who I have had no prior contact with, and I'm busy, I simply ignore their pleas, with the safe assumption that they've sent them to dozens of people, and even if I didn't want to upset them by being non-responsive, they wouldn't notice.
However, when I have nothing on my hands (Fanpop-wise), I tend to check out their content and see if it's any good, and if I think it contributes to the club well, even if I'm not a personal fan of the content, I'll fan it so that fans of the club will prioritise it higher and thus receive enjoyment from it. If it's bad content, I leave it. And I never fan clubs which people ask me to unless I AM a fan of the club, and prepared to contribute content and join in at some point down the track to and with that club.
But this is merely my own reaction to such questions. From the points you have raised: