Originally Posted by
etch5895
You may not have gotten a stamp but the immigration officer certainly scanned your passport when you entered. There is definitely a record of you entering so I would be surprised if you encountered any difficulties leaving. That said, it is sloppy for them to not stamp your passport. Did you enter Schengen in Frankfurt?
I am 100% certain that no definitive, wholly accurate electronic record of my entering and exiting the Schengen zone exists even for just my common carrier flights using only US passports within even just the past 12 months.
Whether or not my US passports should be stamped or not by Schengen passport control still varies a lot in practice. Some Schengen countries routinely skip stamping my US passports at Schengen passport control while other Schengen countries routinely stamp my US passports despite my presentation of the same international travel docs.