Does parental controls on Mac actually work? App controls seem to be a joke!

I can easily set up parental controls, and limit the apps my son has access too, the time he can get on the computer, etc. But none of it seems to work correctly, or fully.

The main thing I'm trying to do is limit a specific computer to certain apps. First thing is that not all the apps on the computer show up. Then, things that aren't apps do show up. Then when I've finally set it up, what little I can, there are usually issues with some random file with a pop up menu saying "you don't have permission to access or use xxxx file". One I'm currently getting a warning for is unrar3. One would assume it's related to RAR files, but there is no unzipped on that computer to deal with files like that. First, I can't find that file anywhere with any kind of searching on the Mac (nor on the web!). Second, even though it gives me an option, as administrator to allow use once or always, that simply doesn't work. Seconds later the pop up comes back. That makes the machine unusable - even if all the selected apps work, you can't get anything done for having to respond to that messaged every few seconds.

does anyone know how to make this "feature" actually work, or if not, some third party app that steps in to do what Apple seems unable (or unwilling?) to do??

thanks