I gather that the point was they didn't require someone with radar to see them, they turned on ADS-B so it would show up on all the usual flight tracker sites.
Let's remember that the historical name of the city is Königsberg. After the occupation the Soviets executed an ethnic purge of the locals and annexed the land.
So, do you support a wholesale reversal of WW2-related border changes? Because in that case, your country would have to surrender Lwów and Munkács.
(And Croatia would have to give up Rijeka to Italy. And the whole Alsace-Lorraine stuff would return. And I'm not even talking about Germans returning to Czechia or Romania.)
I don't know what the criteria were to avoid the purge but I know personally a Russian of German parents from Kaliningrad/Königsberg. A certain of ethnic Germans were allowed to stay.
In a sense they are, because whatever European territorial changes happened after WW2 were supposed to be the last ever and to stand for all eternity, as stated in the Helsinki Accord of 1975.
Of course, this agreement has since been violated, notably by Russia.
More often than not, it ends well. FONOPS are a pretty common occurrence and usually end (at worst) with a friendly interception and escort out of the contested airspace. Usually even that doesn't happen.
Pretty sure I learned that the last time Kaliningrad was in an HN discussion.