I'm just mentioning the anecdotal evidence we've seen, not saying that rust can't occur with dino oil. There have been a couple guys who found rusty roller bearings on their crankshafts after long term storage with full synthetic oil, for example, yet cranks with a little brownish varnish on the bearings were rust free.
I'm the opposite of an oil snob, running $12/gallon Walmart TC-W3 2-stroke oil in my H2 and Valvoline VR1 in my 4-stroke non-roller cam motorcycles. Maybe you and I just remember the good stories about our chosen oils.
