My 2 cents added in would be that 3in1 oil doesn't bother me, per se. I use it myself and have worked on a LOT of cameras. including the Pentaxes. The most important thing in oiling anything untrained is the tendency to oil things that are not supposed to be oiled, and causing all sorts of problems. For instance, try oiling a Kalart rangefinder. It'll never work again till you go back in and get your oil out. A wee-tad of oil on a gear is usually harmless, but NOT on flat surfaces that have to slide across each other.
Far from harmless. Oil on a gear can attract dust and form a grinding compound, with predictable results. A very effective way to ruin a watch or clock is to oil the wheels and pinions.