I only had one set of keys, which can cause unnecessary logistic complications when you have visitors. So I set out to get copies. Hala Targowa seemed like a good place to go: It's pseudo-ancient outward appearance houses many different stands and services under a bravely curved concrete roof.
I had a helpful native speaker with me - anything to appear respectable and deflect all uncomfortable questions about security and permissions and certificates necessary to receive a legal copy.
But there were no questions asked. Instead, I received a 1:1 copy of my keys. Upon closer inspection, the new set gives the same instructions as the originals: "Nie kopiowac" - "Do not copy".