it might matter to a future stayer at this prop who intends to use a GC knowing that this prop has in the past not really been up to speed on the usage of GCs in order to prepare for a potential problem the night before instead of trying to checkout and running into a problem when they might want to leave quickly, like for a scheduled flight........

I see. Besides the problem I had with the first few stays, they know exactly what to do with the GC to process :)

I don't ever think they will dare to take more than they supposed to, but kidnapping my card and not giving back to me is unreasonable. They don't even offer sending it back to me - I don't visit Berlin often, so I can't really pick it up later.

Those of us who think the glass is half full would look at this hotel as one where if you want to use a GC, you can, without worry, as another FTer has taken care of breaking them in for us. ;)

No
You can switch cards.
If you are platinum preferred, the card will be charged to that on file and you don't even need a card