Why don't you disable this?? 
I do.

Several people have wrote to me in the past about the "need" for the "Run As" function. I have never used it and as such, I have it recommended to disabled with XP. However, the XP information has been ran through and attempted to be "broke" many times over, but I have not done such a through investigation with Vista.
More then likely, since I have had this service disabled and have found nothing wrong with it, it will be recommended to be disabled in the future.