If their concern is bandwidth then I think I can understand a free WiFi provider blocking "Photo Sharing, Visual Search Engines". I would hope that anyone batch uploading their days photos to Commons would be considerate of such Free Wifi, but to be honest doubt I would be. As for the issue of photos on your laptop in a public space such as a train, I've often sat on a train cropping, naming and reviewing photographs before uploading them later, people do sometimes look and occasionally comment. But I figure nobody will be offended at photographs of steam trains and Georgian antiquities.