Like which one? VBS scripts? PIF shortcuts on 2k/XP systems? Maybe WMF files?
How often do you think regular users use CMD or COM files? OCX are those badass ActiveX controls that everyone fear.
Blocker won't affect those that are already on HDD. I'm working with such stuff more since i work with AVs nearly all my time and i haven't got a single warning. Ok, i lied.
I got one about VBS file in some modified NVIDIA drivers (DHzer0Point, some color correction script which i allowed and it worked fine after that).
You should also fix the Default extensions list checkbox in Blocker. Some user reported that it gets checked by itself when you run Simple interface. Still need to verify that...