People, we need to talk

For those of you who have lived in Switzerland, this is nothing new. When one is in a restaurant at a table and there are places free, it is commonplace that strangers ask to join you. Well, welcome to North America! We were in a small coffee / bagel / tea restaurant in Waterton, Alberta, Canada and wanted to sit outside. As no table was completely free, I asked if we could join the two men at a table meant for six. Sure, but then they left. Today we found ourselves in Sturgeon Bay, Wisconsin. Two people mid-fifties were waiting for a table. As we were at a table for six - again - we invited them to join us. Oh, no way, Jose.  I guess it is better to spend the evening waiting for your "own" table as to join others. I find this very sad.