I just don't see the point in Barry Doe! A self proclaimed 'fares expert' who is usually so far off the mark it's laughable. He also calls himself a timetable expert - he's no good at that either! Best thing to do with anything he says is either not to listen in the first place, or ignore it if you do!!
Is he always that "far off the mark"?
I'll grant you he can be somewhat old fashioned in his thinking, and is obsessed with walk-on fares, but he does make sensible points from time to time such as avoiding websites that have extra charges for selling tickets.
I think in this case he is going OTT. Yes Caledonian Sleeper got it wrong, and should have had a simple one line statement on their website, stating that the following tickets cannot be purchased from their website until 1 April, but could be purchased from the Scotrail website or at stations. But to accuse them of mis-selling is probably going too far.
I imagine that their focus was on getting the new system up and running and this frankly was an oversight.