By placing an entry in RunOnce from the logon script, it would effectively run every time, or at least until such time as you stopped stuffing RunOnce from the logon script. If you placed it in Run, changes to the script would not stop it, unless you specifically added code to the script to remove the Run entry.
_________________________
Give a man a fish and he will be back for more. Slap him with a fish and he will go away forever.