I guess there was no fingerprint analysis.
The "who did it" is of course a completely open thing. But such gestures as well as the other side of gestures were used on quite some occasions.
Your theory about the locals is IMHO quite good. However it could have been a case of a crew wanting to get out of the mess as well....
Here:
"Again, allied personnel nicknamed all German tanks "Tigers". I would also think such a "satisfying" occasion would warrant a photo of the tank. With 25 mm thick belly armor there is no way a 20 mm ricochet would do anything more than bounce off. If the tank was leaking fuel it might have caught fire, but that adds nothing to the argument that a Tiger's armor could be penetrated by a 37 mm M3 gun."
I somehow thought they were also nicknamed a panzer, - or did an allied soldier never see one?
As for the photo opportunity, - absolutely a minority of WW2 fighting population carried a camera, and what we have available on the net is but a glimpse of the lot. I have had the luck of being a guest at the IWM WW2 photo archives, so I'm not too green on what is there and what isn't. Being exposed to death every day doesn't also exactly make you into a japanese tourist collecting for the album. (Sorry Japan
)
On this forum, years back, by the way, there is an account of an M8 killing a Tiger from behind. Many shots and no range.