I have used SI for over a year and they have always paid on time. My last check was over $400. One of the sites in question in that forum:
http://spread-your-legs.com/
clearly violates SI rules. It is the responsibility of the webmaster to be familiar with the rules.
Having site listed such as "wet teen panties" and trying to state it is a not an adult website, because they are wearing clothes is frankly BS.
That link pops up teen mail which is obviously a porn link. SI's advertisers don't want to advertise on places like that. There is no borderline here - Doodle or whomever broke the rules. As anyone who has been in SI's forums knows - he won't get paid.
Some people think that SI will throw anyone out just not to have to pay them. This is also BS. If you make an honest mistake, like not supressing an exit popup when a link to them is clicked (which I did by mistake on like 1 out of 80 links). They will let you know.
If you link to adult sites, or foreign language sites, forget it.
SI is by no means perfect, but they have paid me and tons more every month. If you are doing something that coud be considered borderline, write them first. They have approved two of my ideas that I did not think they would.
SI could use some work, but not in the area of paying people on time.