You know those systems in hotels where you need your hotel key card to enable the lights? My first run in with one of those was a scary one. I guess not as scary as my more recent experience — where the lights did not work at all without the card. The first system gave you light for about a minute until you needed the card, presumably enough time to find the little slot and put your key card in. Well, I had never even known of such a system. By the time my convenience lights went out, I was very inconveniently in the middle of the room, not knowing quite what happened. Suddenly, a coffee table and other normally safe items became dangerous obstacles waiting for a moment of bad luck. Add to that the curtains — the ones that block all light to let you sleep in — had been pulled closed by the person who cleaned the room. There was no light. I waited and waited, eyes adjusting slightly helped by the faint glow by the door. I crawled towards the light, avoiding the nasty coffee table in the upgraded room, and opened the door to the hall. Then I saw it. A slot for the door key to enable the lights. I was saved!
I also discovered the hard way that this device controls all the plugs in the room, and my laptop shut itself off when it ran down its battery.
So I come, finally, to my tip: I discovered that ANY card of similar plastic will work. So I keep an old card (something expired and not tied to a bank account, or a hotel key I forgot to return) and insert it. Something I could live without if I forgot it. I still turnout lights and save energy for the hotel. But my laptop works like a charm when I need it, I don’t find myself in the middle of a dark obstacle course, and travel life is a lot smoother.