Many years ago, working as a ramp rat, I had the misfortune of driving a tractor into a 727. Entirely my fault, owing to inexperience and lack of awareness. There was only a scratch to be seen on the fuselage, but not being a mechanic I didn't feel like making any judgement on whether or not it was something to be concerned about. It was not a very nice experience having to go up to see the old man in the LHS and tell him I'd banged his aircraft. It was just as unpleasent having to go see my boss and tell him the same story. Got a stern telling off, and was then congratulated for reporting the incident. Was told that I would never be fired if I duly reported any and all damage, unless of course I made it a habit of driving machinery into aeroplanes. Was also told that failure to report any incidents would see me out the door in great haste.
These days I earn my keep as a trainer, and am passing the same lessons on. Never, ever, under any circumstance fail to report a damage. If you see an "old" damage, contact engineering or the skipper. Don't ever assume anything. If you bump into the aircraft, well, shyte happens. I'll love you a little less than I do now, and you may safely expect some minor verbal abuse if you've been an idiot, but that's where it stops. Having a blame-free culture is paramount in ensuring a safe operation.