We took the Thalys today from Rotterdam to Paris. As we had booked 3 months in advance, we had reserved the exact seats we wanted, which were 4 second class seats facing each other with a table in the middle, for our family of 4. However, since the train began from Amsterdam, we boarded an almost full coach, and our seats were taken. I apologized, and said that these were our seats, and no one moved. One couple eventually said that they needed to face forward, or one of them might get seasick, so rather than argue, I put our two kids in their seats, several rows up. But those were the last two open seats on this car, so I had to ask again, more forcefully, that the others let us have our seats, so that we didn't end up having to leave our kids in a separate car, or else all 4 go searching for empty seats. They seemed to do this rather begrudgingly. I have to admit that though I allowed this to occur, out of politeness, I was disappointed that what I had imagined did not come to pass, which was the 4 of us having our packed lunch together around one table on the train. Is it the cultural norm, that you reserve specific seats, but then don't expect to actually get to use them?
Just curious to get input here, thanks! It must be said that our two kids, at 10 and 13, were only too happy to ignore the countryside, and have unfettered access to their electronic devices, as the adults were half a car away.