Hopefully our Dutch friends can give a simple answer for this.
We land in Schiphol end of month, and immediately take the train to Ghent. We have already purchased the tickets, not using Thalys as if we get lucky we can just make the train that will get us in an hour early (train from Antwerp to Ghent is hourly). I am confused regarding the "supplement". I have seen postings how this is currently not necessary if traveling out of Amsterdam, and in fact the tickets purchased on NS International, Schiphol to Antwerp Zone are marked "As part of an international journey no Supplement is required when travelling (sic) with the Intercity direct." And thus the confusion, as I am not sure what we are traveling. There are many trains from Schiphol to Rotterdam, most change across the platform for the Antwerp train, and a couple do not require the change. Can we just chase down to the train station and hop on any train and not worry about this? The train that we hope to get lucky and grab is 20 minutes after we land, and we'd love to save an hour if we can, however this is one of the trains that does require that quick change in Rotterdam to go on to Antwerp, and I don't think I would be able to figure out how to purchase the supplement quickly if we really need it (Footnote re quick timing -flight from US is through Frankfurt, so will already have been through immigration there, and we are carry-on only). I would hope that if there were an issue on not having complied we could plead lenience based on what printed with our ticket, but one never knows. TIA.