Basically (and I'm not an expert here), the Uber rich get tax free spending money without taking big taxable salaries by leveraging their assets for super low interest loans. Current tax codes don't consider these loans as taxable income, but they're being used for the same things us peasants use our income for. By considering these cash flows as taxable, billionaires wouldn't be able to hide behind the "it's net worth not liquid income" bullshit these use to dodge taxes.
I imagine they could if they knew exactly what you did and when, but if it doesn't get discovered until later and nobody knows what happened, it would probably be a bitch to figure out