Same reason a grocery store will spend $100 to catch and prosecute a shoplifter for taking a $2 candy bar. It's more expensive if they don't go after tax cheats

Same reason a grocery store will spend $100 to catch and prosecute a shoplifter for taking a $2 candy bar. It's more expensive if they don't go after tax cheats. (I'm not making a judgement on this specific case, but rather the idea of spending more money than you will recover in general)