Best is indeed to try their twitter, and don't hesitate to post their answer here ;-)
Apparently it needs to fit in the hand baggage allowance
Which is rather awkward.
The stroller is this one, which is significantly larger in all dimensions except one. As my daughter is now slightly more than 15kg it's also not the best idea to wheel her around too much in it.
Let's say I give it a go and I end up having to check it? What is that likely to cost me?
I might try to assess whether I need it at all. It's schlepping about Schiphol that's my main concern, as well as getting from Leiden station to the hotel.