In the U.K. those seeking jobs while receiving unemployment benefits could have those benefits cut off if they quit unpaid volunteer labor. The volunteer labor is part of a work experience program offered by the Department of Work and Pensions.
If a job seeker expresses an interest in the work experience program they have one week to quit without penalty. After that, if they quit then they could lose their benefits.
The program sends those seeking jobs to work for a period of up to two months at supermarkets and other stores many of them big name outlets. Those in the program can work up to 30 hours a week with no pay. There is no guarantee of a job after the program is over either.
Some participants claim they were not made aware of the provision to quit within the first week. In effect the work experience program is a giant scheme to provide some companies with unpaid labor. For much more see this Guardian article. Unemployment is high in the U.K. particularly among young people.