I'm a bit confused as to why you are even using source control if each author has a different version of the same project on their local drive. The purpose of source control with RoboHelp is to ensure that all authors are working with the same project. Suzie's project should look identical to John's and so on.
Assuming Source Control is properly set up and configured, I would think if you deleted a project from the Source Control repository it would very likely affect the other users.
What happens is that sometimes someone will go in and change the name of a topic that has already been created and when that happens, RoboSource doesn't seem to play nice. The other authors who might want to edit that topic cannot because RoboSource cannot find the old topic name. Also, there have been times when a folder has been deleted in RoboSource but shows up in RoboHelp anyway because the folder that was deleted is still on our hard drive. I know one solution is delete the .cpd file and rebuild RoboHelp, but at this stage of the development, with everything set up the way it should, I am unwilling to do that. Since we are newbies to RoboSource and did not have any time to look at it or play with it before we were told to use it, we might not be doing the things the right way. That being said, we feel development would go faster if we took it out of RoboSource.
Sorry for the long winded explanation and hope I haven't been too confusing.
I can understand your frustration with errors in RSC/RH integration. Strange things do seem to happen.
In answer to your original question, I do not believe that removing the project from source control on a single author's machine takes the project "Out" of source control for other authors.
The database of files on the RSC server will remain the same and the rpoject will be maintained locally. This can be a good way to clean up a project and then add it back to a new RSC database later.
Leon, you might want to be careful with renaming items in source control. If you make a change in source control, RH may not know about it. We generally make changes in RH, letting RH communicate the relevant changes to RSC. I don't usually make changes directly in RSC unless there's a problem.
I might mention that such problems tend to occur when there is a RH crash during certain kinds of operations. For example, say that the help author renaming a folder when his or her pc crashes. This kind of interruption can leave RH with one set of information and RSC with another. Then you can get stuck with having to manually rename and delete things to get them sync'd up again.
I'll agree with you on deleting/hiding folders in RSC. Sometimes there gets to be quite a bit of visual clutter, but you probably don't want to totalll obliterate the old items.
So, I tried it out on one of my test systems.
Removing the project from source control will change that user's view of the project.
However, the user can re-connect to the project again (by opening it from source control) which will copy all the files back down as if it was new again.
However, if the issue you are having is that your authors are seeing different versions of the files, you should check on the status of the files for each user.
I reccomend you have each user save and check in all files.
This should put all changes back up. Then, when you open the project, have each user download the latest from the server. If there are any inconsistencies, you will get warnings about them.
Hope this helps.