All this talk about soft breakfalls got me thinking - how often do you worry about your uke's 'other hand' ie the one that did not initially attack you? If your uke can touch you with the other hand, they could cut/stab you. This is very apparent in lots of the breakfall type ukemi where uke turns in to breakfall, for instance kotegaeshi or shihonage, and can often slap tori on the back or neck as they go over for the fall. Not nice if they had a weapon in it.
I think I'll look at this next practice - see if I can touch or slap my partner during the final ukemi and get that knife in