When I purchased some Bournemouth tickets the other week during one of their "ticket release" days, there were a lot more than 3% of tickets left for that game when I went on - granted they were in the gods, but there was still plenty left.
They were planning on holding more ticket released throughout the season (Especially for the home games after January) so I would think there would have been more than 3% of the ticket offerings available or else it would be pointless.
I genuinely don't think the club are being truthful here. They are making out that because there arent many tickets left, it's insignificant that its going to be £66 flat rate as of now. The reality ism, the club know damn well that there wont be no shortage of takers (especially tourists) and therefore have seen it as an opportunity to make a little bit more money (probably pay for 2 weeks of Rashford's wages!)