A common mistake when using dd is to create a file in /dev which fills up the space of / and may stay silent until / gets filled up by something else that will fail.
Would it be OK to add this in /etc/daily? find /dev -type f ! -name MAKEDEV -delete AFAIK /dev should have only MAKEDEV as a regular file. hier(7) says /dev only have block and character devices with the exception of MAKEDEV.