Anytime you do a clean on a Titanium mobile project, the build/android and build/iphone directories have any existing .gitignore files deleted. This is bothersome when those files are the easiest way to ensure that the build/iphone and build/android paths exist when storing a project on git. If they don't exist, a user attempting to build the project will get an error on their first attempt.
It would be ideal if, when a clean is performed on a project, that any existing .gitignore files were left untouched in those directories. Running a git clean should restore the project to the state it was check in with.