What do you suggest in situations where you can’t do that? Last summer, I travelled on a sleeper train from Lisbon to Madrid, which are in different time zones. At the time that I set my alarm, my phone had no way of knowing that it would automatically jump an hour ahead in the middle of the night.

In that specific case, it woke me up according to local time, which is what I expected. But what if I had crossed the time zone boundary less than an hour before I wanted to be woken up?