Jason Feifer, Editor in Chief of Entrepreneur Magazine, shared how he was kicked out of a coffee shop for using his laptop. An empty coffee shop. On a Sunday. Whether he needed to work for 30mins or half the day, the owner was firm and even refunded their coffee to get them to leave.

Opportunity? I think so. Here's how I'd do it: Set up an easy-to-use PAYG/drop-in booking form (or sign up to an app that does this for you). Connect this to your doors/wifi/etc. Tell the coffee shops to send laptop users to you. If you can get the overheads low enough, you can even print cash on weekends.