[BirdOPrey5]

There's a lot to read there but if you have a 'yellowcard' usergroup that can view the forums but not post and you want to stop them from reporting a post then just put the report post graphic(and link) in an if statement to not display it to the yellowcard usergroup. The exact syntax of this I'm not sure off hand but it's commonly used in examples all around the site. I think it may be:
<if condition="$bbuserinfo['usergroup'] == x"> {nothing} <else /> {report link code here} </if>
where x is the usergroup id number of your yellowcard group.

In terms of non-complete bannings though I have had bad luck with them. I used to have a forum called 'Alcatraz' where 'banned' users could post without any advanced bb code features, sigs, or such... regular users can visit Alcatraz to 'taunt' the prisoners and such and it was good fun for a time until some people got so pissed off they would slow down the site by continually reloading the forum over and over again- giving them access to any forum, even if only read only, a single determined user can initiate enough queries to slow down and clog the site- so ultimately I had to go to complete bans because that way if they hit refresh a lot there was only 1, if any, queries generated.