We cruised the Danube with Viking River Cruises in May, 2009. The trip included only a night and a day in Vienna, not enough but we accepted that based on at least having an evening there.
But Viking didn't come through with the evening they had promised. They said there was a problem with bridge construction that would delay arrival in Vienna, and tied up instead at the tiny village of Krems, where there was nothing to see and nothing to do. Night in Vienna or night in Krems? What would you choose?
Assuming they really couldn't get the boat to Vienna, they could still have taken the passengers. It wasn't very far, and they already had buses taking people into Vienna for a concert. Those of us who didn't sign up for the concert should have been allowed to go on those buses, just so we could have our promised evening in Vienna. Instead we got to hang around the ship listening to wretched music or going to bed early.
Some companies make sure things go right for their customers even when something unexpected comes up. If our experience is any indication, Viking isn't one of them.
The complaint has been investigated and resolved to the customer’s satisfaction.