To be fair, put the usernames of the people who are "in" on a list (not post numbers). This way, you do not count duplicate entries with the same username. Everyone who is "in" has an equal chance to win.Very nice PIF! Since I recently won a PIF, I will stay out of this one. @Atlantic59 made a good point in another PIF thread, makes for a little more work, but certainly not much.
Make a list starting at #1 and only put post numbers from those who are in for the PIF, exclude those of us not in. Then draw from the line numbers only. That way those not in do not dilute the results.
This is very kind of you!
This also removes people who are not "in" from the selection pool, as you wrote.
RANDOM.ORG - List Randomizer
This page allows you to randomize lists of strings using true randomness, which for many purposes is better than the pseudo-random number algorithms typically used in computer programs.
www.random.org