Isn't that already a problem, for instance if using the Season as part of the filename/path and it is not populated in the database (or can't get a connection) you get odd directories? I believe I have seen this happen.
There are programs like dbpoweramp that provide a very rich set of file naming capabilities, with "if" structures within the naming string. But I will be the first to admit it is complicated, and I am a programmer. But then again I bet very few people go to the advanced file renaming section anyway, so if something like that were implementable it could be hidden in there to keep the GUI simple. I am trying to think if there are any open source implementations of something like this that could be used (and hence the schemas would be familiar to more people) but can't think of any right now.
This thread only caught my eye because it is something that I had thought about, but never bothered to ask, since most of the things I record are TV shows, and I can handle the movies by manual methods. But it sure would make the whole setup more "family" friendly if I didn't have to be in the loop :-)