This is why you should NEVER be in the same plane as the spinning prop and make sure that NO OTHER PILOTS are either. I see guys running their engines at full throttle while in front of the plane AND reaching over to hold it down, NOT a good idea! Don't use locktite on the prop shaft, it will only complicate things as you try to change props or check for tightness. Use a long enough wrench to get some leverage on the nut and while holding the prop in the other hand crank that thing tight. Wood props will tend to compress when they're new so they need to be checked more frequently. If you ever have the least bit of doubt that the prop is not tight enough, by all means check it before you start it. 12,000+ RPM's on a 1oz piece of nylon or wood that decides to part company is lethal to say the least. Let's be as safe as we can, most accidents can be avoided.
By the way, any oil on the prop shaft is not a good thing. If there's oil there, clean it off. Stay safe guys!