Thanks for the input and links. I think we are going to be in good shape here since on the final machine that the application is running on, we have tight control over which cameras are plugged into which USB ports. We added an internal 4-port USB card and the user will be unable to move the cameras. Each camera is assigned a dedicated port on the PCI card and cannot be physically moved. I named each camera in MAX and over the last week none of the cameras has 'moved' in heavy testing and numerous reboots.
Interestingly these are Microsoft cameras so serial numbers *should* be unique and reported (they're not high-end but they are not exactly 'toys' or off-brand) and identify themselves properly to Windows.
I think some of the problem was that the USB hub I was using before is very low-end (dollar store!), good for real basic use but not good for something advanced like this, and I have multiple identical cameras that were being moved around further confusing the USB hub. Keeping them in the same place on a dedicated USB hub right on the bus seems to be keeping things straight.
