At lest in Germany the police still uses them to justify random searches. I haven’t been affected by that since I’m quite white (even though I live in one of those zones where the police can more easily search me). In the train and train stations police seems always laser-focused on inconveniencing brown and other strange looking people. They are masters at racial profiling.
For white people those open borders are quite nice and quite open in every sense of the word. The outside borders of the EU are for aggressively and inhumanly keeping people out.
Ok, if you are young, alone and in a train from the Netherlands to Germany (or in similar suspicious places) you might get searched for drugs but that’s about it. And even then those searches are quite random and don’t happen very often.
But the rampant racial profiling sucks. (One example of why that is the case and obviously unfair: I can be lazy and late and show up at the train station three minutes before my train leaves. I do that regularly. No problem practically every time. The police never once in my life stopped me. And whenever I did see them stop someone in the train station those people had one thing in common: they were not white. If I were brown I would have to think twice about arriving so late and hope that the police doesn’t see me.)