I recently upset a cafe owner, in retrospect with good reason, for plugging in my laptop without asking.

What is the currently (evolving) etiquette for using someone’s electricity and bandwidth? If I take out my mobile telephone and use someone’s open Wi-Fi network should I ask?

Etiquette would generally suggest that you should never use someone’s stuff without gaining permission. Never ever.

Generally you’ll be looking for explicit permission either in the form of a “Wifi Available” sign or by asking the staff. However — and here’s where I probably part ways with Miss Manners — there’s also implicit permission.

Implicit permission to use power or network connections include:

• Lots of other people around you doing so without getting in any apparent trouble
• Being in a hotel, convention centre, or similar venue
• Being in an airport or other major transport hub

Those are the only implicitly safe places I can think of to plug in a phone charger or use any open wifi you might find. Can anyone think of others?

Other than that, if you don’t have implicit or explicit permission, you should ask first.