I deleted my previous post because there has been an update:
I signed up for a D-Day tour with Bayeux Shuttle. I was concerned about low numbers but was reassured they would run it no matter what. Yesterday, I received a reminder of the tour with the name of my guide. Today, they cancelled on me. The tour was for the 20th.
Update: Three and a half hours after the computer generated cancellation, I got a sincere email from the owner. It seem everyone else on the tour cancelled and he isn't allowed to give the tour to just one person. He also issued my refund immediately.
I told him had he written to me first I may not have been happy but I would have understood.