If you hide a folder it is still quite easy for others to be able to view them if they follow the instructions at https://cloudbuild.co.uk/?p=501
But most users on a domain/network probably won’t know how to do this unless they really look into it.
To hide a folder from others on a domain/network:
1) Right click the folder you wish to hide
2) Click properties
3) Tick hidden, click ok
If the folder includes confidential data, hiding the folder is not recommended but instead I would recommend applying security permissions to the folder.