I won't even entertain the thought of permitting someone to cut their wedding cake with it.
Speaking for myself, if it's good enough for a United States Marine's sword, it's plenty good enough for my humble dirk.

I shouldn't and don't as I always keep a film of oil on the blade.
Generally speaking, such ceremonial cake/haggis cuttings are well coreographed events prepared well in advance, but in a pinch a wee dab of Scotch on a napkin solves the problem.

Speaking of oil, I prefer something a bit heavier than WD40, which will evaporate completely in a few days. Nothing really beats good old LSA. Also, don't keep your carbon blades in their scabbards; the steel will condense moisture and rust. If not on display, wrap them in an oiled cloth for storage. If you've got wee ones about, lock them away like any weapon, unless you want to come home one day to find your yard ape swinging from the curtains with your dirk in his teeth in the finest Errol Flynn tradition.