I said free and legal insider trading by everyone. People in the company would also be able to trade on their information regarding potential government actions etc.
Some people have very disproportionate access to accurate information, and this disproportionate power and influence. You can't dismiss the harm abuse of that can cause. Just look at all the staged games done for the sake of betting profits.
So, the situation will be no worse than it currently is, but with the upside that more information would be available, and tons of money would not be wasted on stupid investigations.
I do recommend you watch "American Greed" on CNBC.
Markets are information aggregators.