Earlier quoted context omitted.
1. Yes, I've always had to use my passport with my Eurail passes; though often it's to prove I'm an American who is eligible for the cheaper pass. 2. No, only in certain countries. I've bought SIMs from vending machines in Iceland and Denmark. In Italy the merchant made me seriously promise, I really mean it to send him a photo of my passport as soon as I returned home with my SIM. He gave me his personal gmail addre…
From June 2017 there will be no extra dataroaming charges in the EU. So you could buy a non-registered SIM card in The Netherlands (you can even buy them at the checkout counter at the supermarket) and use it all over EU member states. Strange situation...
I hadn't been to Europe since 2004, and on my subsequent visit in 2011, I just casually told my wife "we'll just buy SIMs at the first country we go to, surely they've sorted out this stupid roaming-when-you-travel-a-few-hundred-miles thing by now." WRONG.
So glad this is coming to an end. I've wasted far too much time and money country-hopping and having to spend 30-90+min in each country trying to get a working mobile phone. Locals probably don't realize how bad it is, but on prepaid plans you often cannot roam in foreign countries at any price. So as absurd it is to pay ATT here in the US $60 for 200mb or whatever insane rate, sometimes I wonder if it's worse to spend $40 per country per SIM card if I'm only there for a few days. Not to mention changing phone numbers constantly, assuming you would like to be reached...