Are the scarifiers the weak point? Can you just use them bent for awhile, and just buy new ones?
I think any weak link will depend upon the quality of the box blade, the size of tractor used, the soil conditions and operator experience.
My ROBB is moderately built (72" x 710 pounds) and used in very hard clay, very large rocky soil and has many very hard use hours on it. I broke the replaceable tip off of one of scarifiers early on and it must have been a factory defect as since then no other tips have been damaged and this ROBB has seen lots of very hard use.
I also bent one scarifier a bit sideways when I suspect the ROBB was digging deep in wet clay and got wedged to the side of the tip of a small, buried boulder. Something had to give and the shank bent somewhat- maybe 15 degrees or so. I still use it as is but do have a couple replacements I could install that I purchased as spare parts when I purchased the ROBB new. I can't imagine bending a quality shank along its length.