It should be.  Mind you we run NTBACKUP with batch files to print off the logs and email the users as a scheduled task with a user account.  Most of the servers aren't logged in on the sites we deal with.

I've seen tasks scheduled and created by Antivirus and Update processes created under "SYSTEM".

I do believe though the procedure was a slight bit different to use the "SYSTEM" account.  There is a password involved but I don't believe you ever type it in.   I'd just search for that.

I do know that typically the task will not run if the password is blank.