Originally Posted by
DaviddesJ
I think getting rained on is a known risk for baggage and if your baggage doesn't protect the contents from getting wet, that's on you.
There's a big difference between baggage getting a little wet on the ride in from the plane to the terminal and UA letting it sit for an hour on the tarmac in a downpour. Most luggage will protect baggage from the former, I doubt that hardly any will protect the latter.
Totally
not the OP's fault.