i've seen many ivory ferrules with no pad and they've held up fine. i don't really know what the rate of breakage is with ivory ferrules with pad or no pad. i guess it is a good insurance policy to use the pad, but it would be interesting to get some data on how much it is really needed.
besides the OB shafts, the only other shaft i've seen use the carbon fiber pads is the BK2. interestingly, the new tiger LD shafts, which also use a balsa wood core and i believe an open uncapped ferrule, only uses a fiber pad on the end of theirs.