Although your explanation makes sense on the surface- I don't agree with that, and here is why. A single action has a safety and a double action usually has a 6-10 lb trigger, with a long pull. Just how much pressure does it take with an oily rag to remove a fingerprint??I think a lot of these 'cleaning' incidents are actually folks just wiping the outside of the gun down with a cloth and maybe a little oil. As they move the gun around wiping it, they end up getting their finger on the trigger or cloth caught in the trigger and BANG!
And if you clean (wipe) a loaded gun, that you didn't just load to clean, there shouldn't be a fingerprint on the trigger.
The only accidents in these scenarios is that the original intention was probably not to shoot someone. Sad.