I have a Home Improvement/Painting business, and Angie's List always advertises that that everyone is out to get them. Of course there are people who try to take advantage of homeowners My reputation and repeat business is based on word of mouth. Shoddy work is always a way to get put out of business quick. As far as strictly painting, preparation is a big factor in getting a quality paint job. If you don't prepare the surfaces you are painting you are spinning your wheels, and wasting money, no matter what paint you use. Getting a deposit from a customer is beneficial, but not always necessary. Sometimes it is a godsend, when you get stuck by the customer, which has happened to me more than once
Back to the article. You can add water to all latex based paints / thinner to oil based paint. The tinting base has absolutely nothing to do with it. Say you are working outside and throughout the day you have to add a little water to keep the same consistency. If somebody really tried to add 20% to 50% water they no longer would be painting they'd be performing a whitewash or pickle finish.