From Elizabeth May’s post, this is a good summary of the harassment technique; from a Gavin Schmidt email:

The contrarians have found that there is actually no limit to what you can ask people for (raw data, intermediate steps, additional calculations, sensitivity calculations, all the code, a workable version of the code on any platform, etc) and like Somali pirates they have found that once someone has paid up, they can always shake them down again.”
http://www.desmogblog.com/elizabeth-may-informed-look-east-anglia-emails