Funny, I posted about this on CC yesterday in an excursion-related thread, though I didn't mention the particular cruise. I had noticed that the same thing happened to us, and something similar to the Byrnes.
In Bordeaux, the Medoc tour and luncheon at Chateau Pomys for which we were wait-listed was totally canceled. Regent seems to have randomly assigned substitute excursions not paying any attention to conflicts. We, too, were scheduled for two at the same time and none on one day. I called and they straightened things out, though I am disappointed at the end result. Although we're in Bordeaux overnight, because of the early afternoon arrival and departure, it really doesn't allow for much time. Furthermore, if you want to see Bordeaux itself and St. Emilion, one has to be done on your own because Regent isn't offering any tours of Bordeaux the second day. Poor planning on their part.
As I mentioned on CC, the moral of the story is to check your excursions every so often to ensure that there are no surprises once on board. Regent should notify us when they make a change, at least by e-mail.
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Eugene