Didn't say it was right, just the way it is.
On winterizations you are required to pressure test the system. If it holds pressure at the time it is winterized and you document that fact, and all your other photos you take show you did everything correctly, then you should be fine. However, if you didn't document the winterization correctly, then the absence of evidence to your innocence is proof of your guilt. Not right, just the way the P&P industry works.
If you de-wint a property and don't document the process, same thing.
Photos, photos, photos.
And that's just the way they are.
Now, if the damage was caused by someone else, then your photos should be able to prove that. Since the system was fine the last time you were there, and your photos prove that.
I've paid for a few damages, only because I didn't have a photo to prove the condition wasn't there when I inspected the property. Fortunately, my mistakes have been small to this point. But, I know what the rules are, I've agreed to play by their rules, so when I mess up, all I can do is try to argue (I have won, but it's rare) and pay up when I lose.
A tip I will share - Sometimes it is hard to quit looking at where you're placing your feet because of all the debris on the floor. Lean into all closets and look at the ceiling in the closet. Do not stop at the doorway to a bedroom, walk all the way in and turn around while looking up.