I have came across this attack once. What happened was when I opened a webpage (torrent listing page),I don’t remember which one it opened a popup and they made it fullscreen, and it was saying that I had visited some bad webpage and govt has found it and I should pay some amount (~300 USD) to get my computer unlocked, I checked the domain and it was the gov domain. And it was asking me my credit card details. I felt something is wrong and pressed the esc button and chrome minimised the screen. Then I saw 2 title bars, I have inspected the webpage and found that they are drawing custom title bars. A lot of people would have fallen for this.