That would be the black-hat way of communicating it to the hotel. The white hat way would be to notice something may be open but don't proceed to investigate -- not even bridge your laptop into the network -- until getting an agreement (usually in contract) to trade knowledge for money.

Both have their perks. I like the legitimate money route. What this blog post describes is more like a grey hat approach than either end. You've got to put in the time and get some creds before the white hat route becomes practical, though, so it may be understandable.