2 for 1 offers

As a person who caravans on his own, I am annoyed that special offers for visits to attractions are frequently '2 for the price of 1' eg IWM Duxford when showing my English Heritage annual membership card. In view of the (in my opinion) high price of entry to Duxford, I am sorely tempted to stand outside their entrance holding up a big notice asking for anyone wanting half price entry to come with me, so that we can both save! Would it hurt attractions which currently offer 2 for 1 deals to stop discriminating against single people, and offer half price entry instead?