About 15 years ago, I worked in a place where people openly admitted to each other that they have lied to their insurance companies about what job they do, their car/driving history etc. to get cheaper insurance.
One time, when I worked in a job, not very well paid, a couple of women told a new starter that when applying for benefits, to ask the bosses for the lower paid days/shifts, for several weeks to make your income appear lower than it actually is, to get more benefit than they should.