Whaaaaaaaaaaaat. This looks really fishy.
With most column shifters, you can go from neutral to drive just by pulling down on the shifter. But you can't go from neutral to reverse without using the safety feature (usually having to pull back AND push up). That would be a suspiciously and highly coordinated effort for a dog to perform.
If it was a button shifter like some of the Allisons have, larger RV's, maybe, but aren't those usually mounted more vertically on the dash versus flat on a console where a dog would be stepping? For the sake of the claim, let's assume it was mounted perfectly flat and the dog jumped perfectly on the "R" button...
There's also the issue of the brake lights. AT first glance, the lights on the rear of the RV could have been just running lights as part of the parking lamp or headlamp switch being on. But nope, they go out as the RV continues backwards, and then they light up again like someone is controlling the brake pedal.
If I had to guess, there's a kid in there who was wanting to be helpful, or a (possibly now "ex") spouse...
It's pretty amazing the acts of stupidity that insurance policies do cover...this is definitely 'up' there, but probably still covered.
Even if it was fresh water they probably won't put it back together. Too much future liability for problems that may/may not be related.