I agree with what everyone has said. But I have to admit I wouldn't do it. I'd be far too scared that it would come around in some way and something would happen to me over it.
Theres so many ways the system can be cheated, not only people who fraudulently claim tax credits, but also people who claim income support and other benefits just because they are overweight, alcohol/drugs dependant, to me, thats fraud too, except the govt allows it.
I dont know anyone who does it, but I do know someone who is on full incapacity benefit, with housing benefit for a private let, they have a brain tumour and doc has signed them off work due to having fits ect. Yet the govt pays for her car. So the same people who are saying she cant work due to fits are also paying for her to drive about on our roads. Its not fraud, but its just another example of a messed up system. she's having a laugh about it, and this year she has been on 3 holidays already.
I worked for HMRC and they have a significant amount of resources that go into fraud. And even if someone is shopped, HMRC would still need their own proof before anything could be done. The amount of fraud that comes from businesses is a hell of alot more than the money thats wasted on individuals, therefor most of there fraud dept is concentrated on business. (tax fraud) - I'd personally be more annoyed about these businesses who refuse to pay the correct tax, a couple of thousand extra from tax credits is nothing compared to what these companies are getting away with. Food for thought.