I'm traveling from Spain to the Netherlands and since many trains are fully booked, I've filtered by 'no reservations required'.
This gave me the option of a night jet from Basel Sbb to Utrecht Centraal.
When I tried to look up this train, it only showed URLs to making a reservation for seating/sleeping on the night jet.
My question: does anyone have experience with NOT booking a seat on a night jet, and still being able to go on the train? Is it possible at all? And if not, why does my railplanner app show this option?