It’s the object security that’s important
Individuals/Groups/*PUBLIC may be granted use/change and when you press F11 it steps through more details
ie: read/change/delete exist (they could delete the actual file) alteer to change the file structure etc.
You should also check the settings on the user profiles. If the user profile has LMTCPB(*YES) this means they can’t run commands from the command line. If the user’s are restricted to using your application menus, then you shouldn’t have any problems.
Martin is right, that would stop most Green screen changes.
However, I don’t think that excludes the users from using the data with Excel/Access/Navigator SQL .. etc.
and using may include changing.