Watering down the paint 50%? It will not cover. I am a contract painter and found that most people that I make a contract with immediately try to change the deal and get more than they are paying for. Sometimes, I let them cheat me as they may have other work that I wish to do but other times I put my foot down. I try to get the client to look at what I have done each and everyday if I am going from room to room. I cannot do this If I spray the entire project at once. Even when I have them inspect my work, they often just do not tell the truth and wish to scam me the contractor for more and more while paying the same as the original contract. Most people have not a clue how much work is involved in painting a house and just assume that the painter rolls out the work with no prep, sealing off the place to protect things that are not painted. All of my contracts state that if anything is in the way like babies, dogs, cars, plants and furniture that I cannot proceed and that it is their responsibility to move this stuff. I always seem to be turned into a furniture mover and never get paid to wrench my back. Fact is most people try to rob the contractor and this article tries to make it seem that the contractor is robbing the homeowners. My sister is a prime example of this as she always goes for the lowest bid yet expects a world class job. This means if you pay $500 for a two day paint job do not expect the contractor to live at your home for two weeks and make only $500.
I used to work at Sherwin Williams. The best thing to do is specify that you will purchase your own paint. If the painter objects strenuously, he was plaanning on making money in the ways this article outlines. You might pay a few dollars more for paint, but you will have control of the quality of what goes on your walls. Never skimp on paint quality.