[em-bee]

isn't that fraud?

[giantg2]

The state doesn't care about fraud when it benefits the state (a man paying support vs the state paying benefits).

[bombcar]

If it's fraud it's on the part of the mother (usually) - the state just wants a clean database to avoid complications; it doesn't actually care about truth.

It's similar to how the justice system doesn't really care about justice, it cares about detailed and systematic applications of the laws, which sometimes coincides.