It's very easy to avoid any problems when working in a cafe. Upon entering simply ask if it is okay to order a drink or two and work on your laptop. If they say

It's very easy to avoid any problems when working in a cafe. Upon entering simply ask if it is okay to order a drink or two and work on your laptop. If they say no just try another place. And it depends a lot on culture / country / area as well. In Slovenia I have never asked as long as there were empty seats still available. It is common for people to hang at a place long after the last order. In my opinion it even adds to the atmosphere because the cafe or restaurant is less empty. On the other hand I was in a group of 4 at a Tokyo cafe which was 90% empty and we were asked to make a new order or leave 30 minutes after the last order.