I know this is a sidetrack, as the thread is realy about tax avoidance not benefits -
but if someone 'works' the benefit system, by moving out from their partner's home to live down the road with their children, and claim single parent benefits, would that that illegal or immoral or neither?
Someone I know did this - in order to fund her PGCE (she was able to claim housing benefit whilst living apart for the duration of the course, but couldn't afford to give up work & pay her share of the rent whilst they lived together.)
I don't think she broke the letter of the law, since they really did live apart, albeit a few streets away - but she probably cost the state a few pounds more than someone on the dole doing a cash in hand job for a few weeks.