What is the policy towards using presumably mainspace-exclusive templates such as Template:User or categories such as Category:Users in the user namespace (or other non-content namespaces)? I see them on pages such as User:I'mDivergent, User:Seaside98/Sandbox/Box3, User:Seaside98/Sandbox/Box4, and more, but in most cases I don't know whether they should be removed or not. On most wikis I've seen, using mainspace-specific templates in the user namespace is disallowed, or at the very least frowned upon, but when I run into pages like these when browsing a category or running a bot in a category, it can cause some problems or just be an inconvenience.