A topless woman walks through Bryant Park following the protest march called the GoTopless Day Parade Sunday, August 23, 2015, in New York. The parade took to the streets to counter critics who are complaining about topless tip-seekers in Times Square. Appearing bare-breasted is legal in New York. But Mayor Bill de Blasio and police Commissioner Bill Bratton say the body-painted women in the square who take photos with tourists are a nuisance. (Photo by Kevin Hagen/AP Photo)

Riot police use a water cannon to disperse LGBT rights activist before a Gay Pride Parade in central Istanbul, Turkey, June 28, 2015. Turkish police fired water cannon and rubber pellets to disperse a crowd gathered in central Istanbul for the city's annual gay pride parade, a Reuters cameraman at the scene said. The police appeared intent on stopping the crowd gathering near Taksim Square, the cameraman said. Taksim is a traditional rallying ground for demonstrators and saw weeks of unrest in 2013. (Photo by Kemal Aslan/Reuters)

Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

A wounded member of the Afghan police reaction force waits for treatment in Alingar, Laghman province, on April 30, 2012. A bomb exploded next to opium poppy fields during a poppy eradication campaign in, wounding two Afghan policemen, police officials said. (AP Photo/Rahmat Gul)

An Islamic religious leader and rebel supporter (R) chant to rally rebel fighters awaiting a rumored Libyan Army advance April 11, 2011 between the crucial towns of Ajdabiyah and Brega, Libya. Rebels continued to hold the strategic town of Ajdabiyah a day after NATO air power struck army troops loyal to Libyan ruler Moammar Gaddafi nearby, helping the rebels secure the city. (Photo by Chris Hondros/Getty Images)

West German police arrest a young man, one of the angry crowd throwing stones at a bus full of Soviet guards making their way to the Soviet War Memorial, 20th August 1962. The crowd were incensed by the death of 18-year-old Peter Fechter, who was shot while trying to cross the Berlin Wall a few days earlier. (Photo by Central Press/Hulton Archive/Getty Images)

Color dyed rabbits are seen in the markets of the Souq Waqif on January 12, 2011 in Doha, Qatar. (Photo by Robert Cianflone/Getty Images)

Emma Watson poses at the winners boards at the Sony Ericsson Empire Film Awards at the Grosvenor House Hotel on March 9, 2008 in London England. (Photo by Dan Kitwood/Getty Images)