First question - Does Valve scan all these files? Are they all (the ones in the workshop) curated and known to be safe? I ask this, because when I used to click on an addon before workshop I would get a warning from Steam saying the file could potentially be dangerous.
Second question- To remove a mod, is the correct procedure to first unsubscribe, then go into the Steam folder>common>left 4 dead 2>left4dead2>addons and remove the vpk files? Or is there also some other area one has to go to in order to fully remove a mod?