P&O discriminate against single passengers

Single travellers have never been favoured in the world of cruise and they are often charged high single supplements when occupying a room that could sleep two or more guests.
However for 2013 P&O have gone one step further in actively discouraging single guests by offering on board credit to past passengers on all sailings of 7 nights or more and all cabin grades, unless you're a single passenger. As a single passenger there is no on board credit unless you book a suite. This to me seems like the worst marketing plan ever unless you no longer want any single passengers or their families on your ships.

Now I understand that cruise lines are not keen on having just one person in the room when they could sell it to 2. 2 passengers generate more revenue from the bars, casinos and shops on board, but they are charging 145 - 180% of the 2 share price which must help them a bit and let's face it not many ships are selling out quickly at the moment. The on board credit that is being offered ranges from £25pp to £100pp (inside - balcony) on a 14 night sailing and only up to £50pp for 7 nights so the amount that they would have to give a single passenger is minimal in the grand scheme of things.

When we spoke to P&O about the new campaign they advised that they cannot give single passengers on board credit as the single supplements are so low. Surely they must have known that by not giving it they would push passengers away and I can only assume that this is what they want - otherwise why not just charge a little bit more and include the on board credit?

 Interestingly they are not even giving on board credit to those sailing in the single cabins on Azura or Ventura and these are still priced at 45% more than the cheapest 2 share cabins.

I have quoted a few 3 generation families for next year who have all sailed with P&O cruises in the past. All of them have been outraged by this decision. By denying  Grandma or Grandad the on board credit P&O have alienated several single passengers, their families and friends. I really hope they know what they are doing with this campaign.