a lot of the western Netherlands is below sea-level. So there is a lot of infrastructure towards transporting water towards places where it can be pumped up into rivers and such
which means that there is a lot of open water, and also a lot of dutch words for different kinds (canals, ditches, ponds, etc) that I wouldn't know a suitable translation for.
Interestingly Jon later tells Melisandre that he would sit on the benches at feasts so it would appear it was only the Baratheon visit when he wasn't allowed in to the feast at all
JON SNOW: When we had feasts, our family would sit up here… and I’d sit down there.
So either he just wasn't shown in the feast on the benches or for some reason they didn't want Jon in the feast
There's also this quote of Cersei about the visit and Jon which could imply they were going to extra lengths than normal to keep Jon out of the way
"I glimpsed him once at Winterfell," the queen said, "though the Starks did their best to hide him. He looks very like his father."
Whether this is Cat cos she doesn't want him around or Ned to keep him safe we won't know
I'll stop looking now, though if the question was asked I can make quite a fan theory out of it :P