More specifically, does "negligible" or "theoretical" risk literally mean "this has never happened"? Or does it mean "it might happen but we can't put a number on it"? I'm aware that this is an extremely unlikely event, but I had a massage + HJ from a woman (unknown status) who spoke of having a deep finger cut (with stiches) about one month prior to my massage. Is there any feasible risk from this? I also shaved my back that day (gross, sorry) and am obsessing over the possibility of blood from her cut entering a nick on my back.