Electric Etiquette

Whilst laptops allow you to work on the move in numerous different locations, not all laptops are created equal, and whilst the RM minibook (aka the Eee PC) allows for the most mobile of movement, it doesn't have the greatest battery (just two or three hours). So once my battery is dead, or on its way out, can I syphon off electricity from the premises I am in? Rather than a one rule fits all situation, it seems to depend on numerous different factors: the role of the premises; whether it offers wifi; whether the wifi is free; and whether the plugs are easily accessible.

Whilst certain public institutions such as some public and university libraries actively make plugs easily accessible, thus encouraging laptop use, others have made no such accommodation, just having one or two scattered around the walls as if the laptop revolution had never occurred. But what about those places where they are aware of users laptop needs, where they advertise their wifi access as a selling point? If I am paying to access wifi in Starbucks can I plug-in? But what about if I am in one of the increasing number of places that offer free wifi? Do I have the same rights?

As always rights come with responsibilities, and laptop users have a responsibility to not cause accidents by trailing cables across gangways or play video or music without headphones, but do we always have to ask about our rights or can some be assumed?

In a climate where more and more places are offering free wifi, actively advertising the fact that the institution doesn't mind you using their plugs would be enough to persuade me to use one place over another. I would love to know if there had been some sort of survey of attitudes to electricity use.