QFileSystemWatcher prints qWarning when addPath() is used like API allows

Many programs seem to use addPath() function in way that it adds same file multiple times (like Qt Creator 2.3.0 and 2.4.0) and that causes qWarning print.
And the same time QT_FATAL_WARNINGS environment variable is very good way to find invalid connects. It however can not be enabled when starting Qt Creator as it exits (at least with CMake-plugin) when project file changes (it also adds project file again with addPath).
The reason that I find this to be Qt bug is the fact that Qt API specifically tells that it is allowed to add same file multiple times and is just ignored ("The path is not added if it does not exist, or if it is already being monitored by the file system watcher.").
My point of view is that functions should not use qWarning when they are used like API tells. Hopefully you think the same...