Been on several GCT river cruises; first ones we were on people changed into smart casual for dinner After that, GCT changed language to "and you don't even have to dress for dinner". Then we started seeing people in jeans, just what they wore during their day tours, with sport shoes, even sweatshirts; one man wore the same gray or blue sweatsuit daily for 5 straight days. We all were glad he changed on the 6th day. No kidding, to tour, breakfast, and dinner, and lunch if we were on the ship. No one challenged. We usually change into smart casual but not always, like the others said, nice to dressy top for women, polo or button down shirt or sport shirt for men. Most men if you hear their discussion, will say they are glad they don't have to dress up anymore.