Rat,

If you're in a sitation where ur using the straight in localizer minimums (GS out, or you broke your airplane) then you'd have the option of using the arbie minimums if you're A/C had the capability to identify the arbie fix, which is used with 3.6DME from the LOC. It's not terribly uncommon, just something to help you get a little lower when you're using minimums that'll probalby keep you in the soup.