1. A formula (known only in IRS) to calculate the cheating possibility of a tax return.
2. Ramdom pick (~0.5%).
3. You are reported in tax cheating by someone and the reporter will be awarded a portion of your tax penalty. IRS encourages this method.
Think about the possible penalty if caught in tax cheating. Your last 7 years (or more) of tax returns may be audited line by line. Besides that, your GC application may be affected and it will definitely affect your naturalization.
Think about which is more whothy, money or trouble. In my opinion, if you can ger rid of the trouble by paying money, just pay the money.
People first, then money!