But we did have 'advance notice'...
As you highlighted above, the pitch was likely to be more prone to heavy rain due to the preceding rugby game. We knew that in advance.
And the weather forecast this time yesterday was pretty much nailed on that the area was going to be deluged overnight. We knew that in advance.
Ok, nothing was guaranteed but there were clear indications that the game would be in jeopardy. It's thus not surprising (to me) that the game was called off.
Anyone setting off this morning / last night would have known they were taking a risk given the circumstances (crap pitch + crap weather)