When we sailed the Rhine, we were looking forward to meeting fellow guests. We went into dinner the first night, chose one of the tables for 6 and sat beside the window. Another couple came and joined us, but sat at the other end. It was great, we got to meet them, but also felt as if we were on our own....and I think we had more space between us than a regular 2 seater. We sat at the same table almost every meal, and it became a joke as we would go to eat, and someone would be sitting there. We'd go to look for another table, but no, they wanted to meet us, so they rushed to get there first!
The only time we had a "runner" was the last night, as we were looking for one of the tables for 8. There were 3, 2 round ones that were taken regularly by a large group from the Philippines, and one other. We had to have someone stationed to get the other one that night.