On runway "obstructions". Heathrow one wet evening a constant stream was landing. The Captain of one flight rang with humble apologies: "Our First Officer insisted I rang to rell you that as we turned off the runway he saw a man laying on the centreline. I'm really sorry to have troubled you, blah, blah".
Plenty more had landed but we got a checker vehicle to have a look and, sure enough, there was a bloke laying on the runway! He wasn't injured but they took him to hospital, where he later died from pneumonia.