You can now set part and assemblies no as read only (v24 feature?), where you then put them is down to your file structure management. For me it's a half way house, but being able to set a file as read-only prevents (unintentional) modification ... an extension to this would be a feature built-in Alibre to browse this file structure (in the context of a library) with the ability to search that library to find the part/assembly you want to add to your assembly based on model properties or name.
Yes, you can, I have been getting this reply since V12.
But it only works as long as AD doesn't decide to change the thumbnail image, which it appears to do pretty often even if the part doesn't change. If that is the case there is no way to save your assembly without saving the RO file too, to a different name, for example. But that is not the idea.
And this does not prevent you from making changes inadvertently and saving thinking it is just a thumbnail change from AD.
I do not understand why there is such resistance at AD to a feature that every other serious CAD has and is a requirement for many if not most companies, possible customers.
Ok, it is "only" file management, not a CAD function, but for many companies important enough to rule out ever using AD.
(Sorry, this has nothing to do with the problem of the OP, but i think it is important for AD's business case)