Dfyjkt

Last night I took a night train from Romania to Hungary. I shared a compartment with another American backpacker (and others.) The border crossing on the Romanian side was normal -- all of our passports were stamped and the border officer recorded our data in his notepad. On the Hungarian side, some sort of commotion broke out further down the train car while we were being processed. The officer who was scanning and stamping our passports left and never came back. As a result, the other American backpacker never had her passport scanned or stamped.

What sort of difficulties might she run into since her passport has not been recorded as entering the schengen zone, nor does she have an extra stamp? What might get options be now, from within Schengen, to get her entrance recorded?

(When I say "scanned", the officers had hand-held devices that read the passport biometrics and I assume, recorded some sort of data somewhere.)

Formally, if you have no entry stamp, it's up to you to provide evidence of the date on which you entered to prove that you haven't overstayed. If you cannot do that, border guards are entitled to assume you have exceeded the limit and to treat you accordingly (that could mean a fine for example or, if you needed a visa, a visa cancellation). As far as the law is concerned, the burden of proof is on you.

In practice, border guards do not always care much about it and any type of evidence could be useful (e.g. credit cards receipt suggesting you were present in Romania). And, as Willeke indicated in a comment, a Romanian exit stamp would be a particularly strong form of evidence. So I would not worry at all. In the unlikely event that the issue even comes up, explain what happened and point to the relevant stamp and that should be it.

Furthermore, as George explained, there is no unified database or system recording entries in the Schengen area. Such a system is in the works and many member states do have their own national system but until now, enforcement mostly relies on stamps.

This happens. I had the same experience in Spain and Italy - in those countries my passport is almost never scanned on arrival, they just stamp it. Twice in Rome Fiumichino it was not even stamped, the border guard just looked at it and passed it back to me. Never had an issue when leaving.

Also there doesn't seem to be a single system which records the arriving and departing passengers - my impression so far is that each country has their own system.

PS. Just remembered I've rode this train too a few years ago, and also didn't get the Hungarian entry stamp (although got the Romanian exit stamp).