Giving the game away

Work experience - a voluntary scheme since last year, when employers decided that it wasn't good for their image if people could be punished for refusing to do it.  It's not the same as the Work Programme or Mandatory Work Activity.  So that's all right.  But now Homebase has been embarrassed by the leak of an internal document which shows the scheme being promoted among Homebase's store managers.  A photo of a dozen or so jobseekers at the Haringey branch is captioned: "Would 750 hours with no payroll costs benefit YOUR store?"  This was passed to Tom Pride and has now been given wider coverage by the Guardian.  The subheading on the document is "How the work experience scheme can benefit your store".  Apparently the Haringey Homebase took 25 unpaid jobseekers in February, each working 30 hours a week for up to 8 weeks.  The Boycott Workfare group claims to have an anonymous source which says that those taking part were threatened with sanctions if they refused.  In one of those tweets which rapidly get deleted, the Finsbury Park jobcentre claimed, 2 days before the Easter holiday, that it had placed 21 people on the scheme in the Haringey store.  The union Unite is outraged.
Homebase has said all the right things.  People on the scheme are not replacing paid workers, they can leave whenever they want to, etc.  And the DWP says that there are safeguards to ensure that people are not being exploited.  But the person who drew up the Homebase document clearly saw the scheme as useful free labour.
If this is happening with the supposedly voluntary scheme, what is going on with those programmes which make no pretence to being voluntary?  Remember that the government adamantly refuses to disclose which organisations are involved, so we don't know how many other companies are benefitting from "no payroll costs".