Is it really that lowbrow? The Pennsylvania Ballet did a very successful, and I thought very stunning, PR campaign with shots of their dancer's bodies. The point of the campaign was that the dancers were athletes, and it came off quite well.
The Royal Danish Ballet has certainly featured less than entirely clothed dancers in ads (in their 2005 Bournonville Calender, a number of the women are topless, albeit in body paint). ABT has gone the sultry mode with some of Fabrizio Ferri's PR shots as has NYCB with the shots in Central Park and around NYC. The fact is that sex and ballet have met, both onstage and off...and long ago.
No offense to Mary Clarke, but the fact of the matter is that it is no longer her generation that we need to attract to the theatre. It is people in their teens, twenties and thirties who we need to get to the ballet - an advertising to that age bracket requires a different approach. What might be tacky to someone who is 60, isn't necessarily going to seem tacky to a 25 year old. A little sex appeal goes a long way... and many dancers have a lot of sex appeal. And since many people have a pre-conception that ballet is prancy, girly, prissy etc., PR campaigns often try to counter that thinking with athletic or sexy motifs. And why not - dancers have such fabulous bodies..
Meanwhile I fear for the state of grammar when a reporter from the Independent doesn't know the difference between principal and principle. Poor editing...