Oddly, I have never run into this before now, so I don't know if this is something new or not. The NWF file can be opened by multiple people at the same time? No msg about opening read-only nor any other indication that someone else in the NWF. Is there an OPTIONS setting that would keep this from happening? Leaving it wide open for anyone at anytime and as many as want can only lead to messed up NWFs where the last saves wins. Not good IMHO.
We've got users doing that. Most users don't make any changes like manually adding/removing files, changing colors, and so on so it isn't a serious problem. I wouldn't mind better multi-user control though, even if its just a warning dialog showing who opened the file/has "administrative" control/etc.
---------------------------------- If you are going to fly by the seat of your pants, expect friction burns. Adopt. Adapt. Overcome. Or be overcome.
Other than making the file read only and assuming that user don't make whole sale changes I'm not sure you can do anything in the current application configuration. However, if you like I’d suggest leaving feedback at the below link. Information gathered is used to improve the application.