The girl in seat 38-J

I'm doing my best not to openly stare, but I can't look away. The Dutch girl next to me is sucking her thumb. With abandon. And I'm using the term "girl" loosely here, as she must be about my age, if not a little older. She's got the whole thumb in her mouth, past the second knuckle, index finger resting against her nose, other fingers clenched in a tight fist, jaw working. She's mainly sticking to the left thumb, which leaves her right arm conveniently free to elbow me every time she turns the page of her Cosmo.

Now, if I were at home, I might be tempted to judge this girl grown woman, but I'm en route to Amsterdam, first stop on my European travel adventures. Far be it for me to impugn her due to my ignorance of her culture. I haven't spent any time in the Netherlands since I was a lot closer to the appropriate age for thumbsucking (by my prudish American standards, that is). Is it possible that I'm on way to the land of tulips, wooden shoes, windmills, marijuana for all, hookers in windows, and... adult thumbsucking? You would think Rick Steves might have mentioned that.