I thought the invite came when you've contributed to the forum with a certain number of posts. Looking thru the members list I see some that are in the PPT with as little as 50 posts.
I think XT18000 gave a very polite informative explanation for those in that section. Thanks XT18000.
I believe there are those that get invited in for various reasons, there are those that request entry and are excepted for their contribution to the forum board, and there's those possibly overlooked due to admin's being busy with other things in life, and there are those that stand at the gates and try to bash and buffalo their way in with insults towards the possible members in the section.
The back button sometimes doesn't even have to be used. Quite often the title itself will hint of the topic on the thread. Option one, don't click topic if it looks like it may not interest you. Option two, open read, contribute and return when interested.
Most everything posted came after a Walmart visit with that sense of humor coupon..........or did it?