I am very happy to see users putting on their own freeroll contests. I think that's great, and it's very generous of people to donate money as prizes here.
As a result, I want to show respect to the contest organizers and prize donors by allowing them to make their own eligibility rules.
That is, if you put up money for a contest here, or if you are one of the organizers, you have a right to exclude whomever you want.
If you don't want the contest open to lurkers, that's fine.
If you don't want certain people you dislike being eligible, that's also fine.
It's your money and your effort, so you can make the rules.
I expect the people excluded from such contests to simply accept it, and if they want to complain, they can start a separate thread to do so. I don't want to see arguing in the contest threads about why certain people were excluded, nor do I want the excluded people invading the thread and attempting to force themselves into it anyway.
Basically, if you want people to let you play these contests, don't be an asshole here, and everything should be fine. Otherwise deal with the fallout from your own behavior.