Morag and I are going to a conference in Glasgow. A colleague kindly drives us to Stansted. EasyJet does not allow you to check in online if you have luggage, so we stand in line. Morag takes out her passport. "Morag, don't tell me you need a passport to fly to Scotland". "Of course you do!" "But it's a domestic flight! Wouldn't a driver's licence be enough?" "Oh no, never! It says 'passport' on the booking receipt".
I can travel all over Europe with my ID. but not to Scotland, which as far as I know is still a part of the United Kingdom. I try not to panic. If I call Staffan he can perhaps bring my passport just in time. I can take a later flight. But it just doesn't make sense. In such situations the rule is: don't ask. As we check in, Morag produces her passport, I produce my driver's licence. No protests. Morag inspects my licence with great interest. "It has your picture!" "Of course it has. Hasn't yours?" Obviously not. And I remember that in the UK it is a matter of dispute whether it is legal to make people have picture IDs.
I must never take anything for granted.