I can attest this too; at Aachen Hbf. in April of this year, I witnessed a group of policemen verbally (in English) warning a passenger for travelling across th

I can attest this too; at Aachen Hbf. in April of this year, I witnessed a group of policemen verbally (in English) warning a passenger for travelling across the Belgo-German border without ID. On a tangential topic, the behaviour of railway staff when checking passports was interesting. With a paper Interrail ticket, they would always ask to see my passport or ID card, yet I don't think I have been asked once when using the electronic Interrail ticket - this is despite the rules being identical for both types.