Firstly, regarding tieing the blades down, I have rented may R22s from different operators and have never foound any of them equipped with blade tie downs.
Strange how training is different - I was always taught to leave the blades at 12 o'clock - 6 o'clock but I do see the sense in making it 7 o'clock - 1 o'clock instead.
Many years ago I was taxying a C172 plank past a parked Trislander when the Trislander pilot decided to do a power check as I passed behind him. I was blown over sideways, shock loading the prop and damaging the wing.. It became an argument between insurers, and in the end they decided I was to blame for being there despite the fact that ATC had told me to taxy behind him.