On my way back to Vienna from Dublin, I was stopped at the passport control in Frankfurt. The police officer was not convinced by my real identity and I have to admit that growing my hair and beard makes me look quite different from my passport picture.
He asked about my name, my place and date of birth and then he asked if I knew my passport number. Of course I knew it and I quickly told the whole sequence to a surprised agent.
He was so surprised that he raised the attention of his colleague who asked me why I knew that. Who ever knows their own passport number by heart?
I do. And the reason is very simple. Every time I board a flight to the US I need to type down my passport number and every custom form requires me to write it down. So I found more efficient memorizing it than looking it up every time.
This of course amused the both of them, but still it was not convincing enough. So I pulled out my driving license and my Italian ID.
After a closer inspection of the other documents is was clear to go and I wished them a nice evening.
It was an extraordinary 10 minutes break in an ordinary airport connection.