LOVE your stickers Duncan! So cool!
I have a sign hanging up on the inside of the hood for when I go to car shows (bonnet is always open at those, to draw the bewildered stares!) It contains this picture I stole from the internet, and says, "Warning- best to keep hands OFF the electric bits"
I didn't feel the need to add the other warning I read somewhere which I really liked: Warning: do not touch. Not only will this kill you, but it will hurt like hell the whole time you are dying"