I've just finished a train journey from Croatia to Slovenia (Ljubljana). There aren't exactly border controls - both are in Schengen. Nonetheless the train was stopped just after the border & almost 30 people got escorted off the train & (eventually) taken off by police. They weren’t Caucasian so I assume they were illegal immigrants or similar.

I didn't take an accurate count but there were 3 women, 2 kids and almost 25 men (mostly 20-35yo).

Makes me wonder why they ended up on that train.