To the first three lines I can't answer, but then neither can anyone else. The fact that none of us know how much it's watered in the morning doesn't support either side of the argument.
To the bit in bold - Yes it has, I never go down to the concourse at half time and they're on every game when it hasn't been raining.
People slip over on all pitches, we just don't make a mental note of it happening in QPR V Aston Villa or Sunderland V Stoke.