I haven't seen any first hand evidence either, but I have seen loads of threads where people make it sound like the end of the world is near. I guess what it sounds like here is a quick wipe with alcohol is sufficient to reduce the risk and a 5 minute soak is overkill. I get it, good to know.
Come to think of it I just started seeing this staining problem arise after switching from Flitz to Maas. Perhaps that is the culprit. Just got some new blades in, guess I will use process of elimination to see what it is. Thanks everyone.