Thanks, Peter. I'm not sure that it answers the concern I have, but it may be a non-issue anyway.

Here's the situation: I'm writing a VB app to automate document creation. It creates an XML document, then opens InDesign, opens the document, and merges the XML. If the document is already open in InDesign, it just merges the XML. That's fine if there's only one user with the document open. But if someone else were to have it open, it might be unsettling for them to be working with (or even just viewing) the document and have it suddenly change.

It should, I would think, only affect a copy of InDesign running on the same computer as the VB app, but again I don't like to make assumptions.

If there's no clear answer on this, I'll just have to deal with it in the event that it arises.