Hi! I am taking my first Tauck trip next month (Rendezvous on the Seine) and I'm wondering about a particular note on the "dress code". I think I saw something that said 'no sneakers', is this meant just for on board the riverboat for meals, etc., or am I not to wear sneakers as my walking shoes for walking tours, etc. either? I do have non-sneaker walking shoes but I've got some super comfy nice white sneaks that would just feel better. Are these a non-no?