So, why does Comodo sell to everyday users, surly not everyone who buys/uses Comodo knows how to configure all the settings? If that's the case, then it's a total waste of time/space. In the AV world how many people just install, update and scan, a lot! I would think The PC Security Channel gentlemen must know, he has just started to work for Emsisoft's malware team.
Of course, if you did have a pdf file, which was actually CryptoLocker Comodo (at default settings, which most use) then it would do nothing. You use to be able to change the setting so both the desktop and internet downloads where secure, and you were protected, now they've taken that option away.