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.
Stacee, I agree with you completely, from adding water to latex paint to taking whites from job to job. This article makes all painters look like scam artists. You get what you pay for people! There is no denying that there are scammers out there but in my experience, most painters are under paid any ways so if you want a good paint job, you are going to pay for it. If you just want a new color on your walls real quick, and that is what you pay for then that's what you pay for people. Most painters get the crap end of the stick and are left with making an entire house look good when it took a lot more than a painter to build the house in the first place. Good painters do not get enough credit. They are not all scammers who are cutting corners!

how Much Does A Paint Contractor Cost

Enforcement of this Act by the Painter-Stainers Company was sought up until the early 19th century, with master painters gathering irregularly to decide the fees that a journeyman could charge, and also instigating an early version of a job centre in 1769, advertising in the London newspapers a "house of call" system to advertise for journeymen and also for journeymen to advertise for work. The guild's power in setting the fee a journeyman could charge was eventually overturned by law in 1827, and the period after this saw the guild's power diminish, along with that of the other guilds; the guilds were superseded by trade unions, with the Operative United Painters' Union forming sometime around 1831.[2]
Here is where this affects you as a consumer. You select a painter with a contract that says 2 coats, $500 down. You give the company the deposit and pick your colors a couple of days before the project starts. The painter goes to the store with your colors and figures out they are deep base. He (or she) not only needs to charge you more for the paint, but he also needs to charge you for a dark gray primer coat. Ninety nine percent of the time that primer coat is going to be really, really expensive since you already gave a deposit.