What happens when companies falsifying the actual dates when stock options are granted to executives?

The people involved get sent to jail for aiding and abetting tax evasion.

This is why someone would falsify dates on an option: there are two important time frames in regards to incentive stock options, and they determine whether the sale of the stock is "qualified" or "disqualified." If you hold the stock for (1) two years after the issue of the option and (2) one year after the exercise of same, the sale is "qualified" and the money you make from the sale is taxed at the capital gains tax rate. (If you get the option on July 1, 2014, and exercise it before July 1, 2015, the exercise date doesn't play into it because the two timeframes run concurrently.) If you sell before then, the sale is "disqualified" and you pay taxes at the ordinary income rates. The difference could be substantial: for every $1 million you make selling qualified options you owe $150,000 in tax, whereas for every $1 million you make selling disqualified options you owe $350,000 in tax.

If you were to grant someone an option on July 1, 2014 but you backdate it and say it was granted in 2012 and exercised three days after, that person could claim to have made a qualifying sale and try to rip off the government for $200,000 per million of profit. The IRS is very interested in throwing people who do this in jail.