What a stupid and careless thing to do
I have been sat in the hotel room for the past hour or two using my laptop. A few minutes ago I decided to take the laptop downstairs and sit in the main foyer.
The room keycard also operates the power supply, which is obviously intended to stop people leaving equipment switched on while they are out. As I went to remove it on my way out I realised that it was on the table at the side of me.
A quick check of the battery shows that it is down to 40% due to running on batteries so long. This rather changed my plans and would only last another hour or so if I do not charge it first.
This is the first time that I have considered taking the laptop downstairs and I managed to forget the power supply.