I will try to answer both inquiries in this post.
to NBdiscgolfer: Well our bag tag series was tied into club membership as well, but you dont have to if you dont want. bag tags could be for a general region and not affiliated with a certian club. it does help the local club if you have them connected though. i allowed people to join in the bag tag series at any time, but i made sure they knew that their chances of cashing out at the end of the season would be a lot lower than somebody that started at the begining of the season.
If your bag tags are ran for fun only, then it really shouldnt matter about having people join in at random times. ours was ran with points system and with cash payout at the end of the season so it made a difference. no matter what, never turn somebody away from club membership with or without bag tags.
to pdxdiscer: the way our bag tags were run was on a points system, so the person with the most points at the end of the season takes home the final cash payout. it grew to be a pretty hefty amount so that provided most people with enough motivation to keep playing challenges and seeking out the lower tags.
also there were some rules in place to make sure that people were out there playing challenges and not hiding away with the sacred tag. for instance the main rule for this was that all bag tag holders must play a minimum of 2 challenges per month not including the monthly bag tag tournament. that did a really good job of keeping the tags circulating between all the people.
i hope that these answered both of your questions,
the first and formost rule on our rules page was HAVE FUN! that is what it was all about.