It's either safe or unsafe
Totally disagree, lying in bed is generally thought to be safe, but if thats all you do you will suffer all sorts of problems - and it is where most people die!
Aerobatics by a trained but inexperienced aerobatic pilot is relatively safe at 3,000'+ but less safe at 2,000' and progressively less safe the nearer he gets to the ground and similar could said of many aspects in aviation!