He is talking about identifying the application rather than the user id.
If the application does not designate a specific user id to run under, checking file properties does not help to identify the process or application which creates these files.
If the application is capable to assign a user id to run under. He can create a user id with appropriate authorities.
Also bear in mind that these tmp files are not all the time in use by the application that creates them. Using a scheduled job to clear the tmp directory on a regular basis will keep your system drive at safe level of free disk space.
Also he can check the individual applications to see if the log direcory or log level can be changed.
Redirecting the log directory to some larger data disk may give the system disk some level of safe regading the file system free space.