Uploading assets which contain spaces - especially in the case of video files - causes some major issues for reporting. It should not be too difficult to have the platform find and replace any 'space' or other non-accepted character with an underscore '_'.
Something like preg_replace('/[^a-zA-Z0-9]+/', '_', $filename); (or however it looks in Java) ought to do it.
At the very least, this should help alleviate client reported issues related to video reporting that stem from incorrectly named video assets. This issue extends to auto-transcode, where a video asset containing spaces gets converted, and the output variants re-use the same file-names as the source. So all videos which contain these characters would encounter issues. These may also get flagged by publishers, which causes delays and client upset.