Check out the new Demand Sync option in the latest beta. If you don't put notes on your local machine, that avoids a lot (if not all) of the issues brought up here.
If you have a Pin or Password, your files are still sitting on your local hard drive. So the IT guy who could reset your password and open up Evernote, can presumable access any of your local files.
Perhaps what you're requesting is for your Evernote database to be encrypted separately (and with a password). In which case I'd guess is a lot do work.
Same thing for the mobile devices. If someone has physical access to your unlocked device, they probably can get to your local files.