I do understand that Grahame, but surely this falls into a different area?
A restaurant is, surely, a business, running with a view to making a profit. If anyone works a night there either unpaid or undeclared then that is, essentially, dodging potential tax and social security payments. Not saying I agree with the fisc's attitude, but I can see their logic.
Same with company cars - some UK companies used to hand them out almost willy nilly until the tax rules were tightened up. My wife used to work in the City for what was then one of the Big 4 banks. They automatically gave a company car to people once they reached a certain level of management (whether or not they could drive). Once that was tightened up they had to change the whole pay structure!
This sort of arrangement would appear to me to be more of a symbiotic "I win you win" scenario. How would they view it if people had friends to stay who helped out with a bit of DIY whilst staying? (Possibly a bit of a red herring I know!)
We are told (http://www.emmaus-france.org/) that there is a real shortage of rental accommodation available for people on low incomes. Wouldn't this be a fab way to help out?