Deny edditing parts of registry

I've found out that some people dont like our corporate policy that after 10 minutes the screen goes to screensaver *kuch* youtube *kuch*

So they found out if they edit the registry in current user their screensaver doesnt pop on if they set the delay to 999999 or some thing like that.

i've found out they edit:
HKEY_CURRENT_USER\Software\Policies\Microsoft\Wind ows\Control Panel\Desktop

Would you guys recommend for setting the right i thought about
USERS\.DEFAULT\Software\Policies

and setting it to
Allow owner full control sub keys only
allow nt autority system full control this and sub keys
allow buildin users read this and sub keys

Allow inheritable permissions from the parent to propagate to this object and all child objects Disabled

i saw in your course that you reprocess all registry settings so they get applyed every time isnt it easyer to take a way the rights to the keys you dont want them to mess with ?

and make sure they cant edit them any ways ?