Hey Arturo,
Petko was explaining the following thing: Even the regulated brokers have the A book and B book clients. A book is the winners, B book is the losers. One of the ways to move more clients from A in B is to increase the slippage for the A clients that trade the news.
This means that if you succeed to make profits on the news they will notice it, and they will increase the slippage just for your account.
I do not say that all brokers do it, but its a practice. Keep it in mind.