limit on max filesize is not respected

basically I have a set max filesize on my settings page and despite this, people keep being able to queue up items MUCH larger than this. This puts me in kind of a bad place of figuring out how to deal with this issue. My internet line isn't so great to be able to seed out multiple full DVDs, etc to people all at once.
The reason these are viewable of course is that I have hard drives with different types of items all on the same hard drive, usually not broken down into music, dvd, bluray, manga, whatever folders. adding all my music folders would otherwise be an impossible task.