Every cold start is with totally dry cylinders and oilways drained off, most oil pumps also empty themselves overnight which is why they are located as near the oil level as possible. Rebuilt engines start up dry apart from what you squirt on during the build, which has gone by the time you get the unit back in place. But with my method the engine is still warm because I never change oil cold, I suck it out in 5 minutes so everything is still oily. Anyway, I never ever get engine trouble down to lubrication issues and I've done it on 50 cars over 55 years, I'm not going to stop now because somebody differs over it. It's far less harmful than a cold start in either winter or summer I'm quite sure. And don't think the rubber flap in a spin-on filter will stop it from emptying, because it won't. As for engine flush systems, they certainly seem to work, perhaps too well if you look at what they bring out of some old engines. But I don't feel sure about putting that stuff in, maybe it softens oil seals, or perhaps hardens them?[/QUOTE
You are in denial. Running the engine with the oil drained is not the same as as a cold start after standing. Flap valves (and anti-syphon tubes in some e.g. ford "pinto") do hold oil in the system running the oil pump with the pickup open can blow air through the oilways, this does not happen on a start. Flushing oil isn't (shouldn't be) in long enouthe to affect seals even if it did. You can always use cheap oil instead.
Each to his own I suppose.
Robert G8RPI.