Assuming your files are on a network, you may be able to have the folders where these files are saved "read only" access for everyone that doesn't need to be able to change them, such as you and the foreman, who would have both read and write access. That's what I've done here with the folder where my library parts are saved.
And I'm sure you're aware of this, but you don't have a software problem, you have a personnel problem.
As Glen already explained, changing the access rights for users on the network is your best bet.
If you're using windows domain on an Active Directory, you can simply go to the Active Directory Users and Computers on your server and add two new group, one with full access to the full access to folders where solidworks files are saved, and one with readonly right to those folders.
Now you can simply drag any users to one of these groups to change their access right.
But if it was me, I simply asked them not to play around with the files, and managed some training classes.
An alternative (but draconian) solution would be to have your IT dept take away their SW installs & give them eDrawings instead.
You need a vault my friend. You might have WPDM already (but you probably don't). It's my understanding that SW will be giving away EPDM lite in 2016. You should be in good shape if you can hold out until then.