Gaining Write-access in a multi-user environment

3 topics, 7 questions:

1) When you try to open (with write access) an assembly file from the "Open"
dialog, SolidWorks will sometimes tell you which user already has the file
open with write access.
On other occasions, it will only tell you that a user has the file open,
without specifying who it is.
Walking/ringing around dozens of CAD workstations in multiple offices in
three cities can get tiresome.
Questions:
1a) Any thoughts on why this behaviour varies?
1b) In the second instance, does anyone have a cunning method to wring the
truth from either the application or the OS as to the identity of the
mystery user?

2) When you try to delete a file which you have previously had open, you
sometimes cannot do so until you quit from the session of SolidWorks in
which that file was open. Presumably this is because it still appears in the
"Recently Used File List" in the File menu
Questions:
2a) Do others have thoughts on this?
2b) Does this have any relevance to topic 1) ?

3) When I try to open a top level assembly with write access, it appears
that I cannot do so if another user has write access to any subassembly
within it.
Questions:
3a) Is that the case? Is it true also of parts?
3b) Is this the answer to 1a? (ie, if a user has the same (eg top level)
assembly open as the one I'm trying to open, I get their name, if it's
several users with write access to more than one subassembly, I don't?)
3c) OR if it's just a single user with write access to a single subassembly,
perhaps I do not get their name?

TIA

Andrew T