I've created a new preposition rule: "guilty of".
In some sentences "guilty about" is correct, though.
There are other glitches, but I didn't get time to refine the rule.
You may consider changing it later, meanwhile, this is the what I have for now.
<!-- English rule, 2017-04-17 -->
<rule id="GUILTY_OF" name="guilty of">
<message>Did you mean: <suggestion>guilty of</suggestion>? (Incorrect preposition)</message>
<example correction='guilty of'>If you are offended by my posts, then you are <marker>guilty about</marker> something.</example>
<example>If you are offended by my posts, then you are guilty of something.</example>