With QlikView Server serving the clients with the document you can set it up to refresh gracefully without the need to re-open the document.
Check the Server tab under Settings - Document Properties in QlikView.
So if you have document A opened via Server and the document A is reloaded by someone, QlikView Server will know that the document has been updated and load the new document in to memory and do a seamless switch, depending on the graceful refresh settings you use.
There should be more information on this in the reference manuals.
Not really no, since the QlikView document has no real relation to the QVD file except that it's specified in the load script.
There are of course always ways to work around these things, like a macro that checks if the QVD file size has changed and initiates a reload. However, there's no such solution out of the box.