Tom, thanks for the filter.
I can't replicate the behavior you described w/ the requestprocessor also filtering something that was handled by your filter. If you turn on DebugP and LogDebugP in your site map/ACS Kernel parameters you should get RP logging notices when the request processor is invoked; are you sure you're getting these notices, and that your registrations are done in /home/aol3whatever/modules/tcl/init.tcl? (If you put your code into /web/sitename/tcl/init.tcl, it will be run after rp_filter is registered, so then the described behavior would make sense)