Actually, in the USA that is common anyway. Before my stint with the U.S. Navy as a contractor, I worked in private industry and rose to managerial levels. There were many cases where we were instructed to low-ball and we learned WHY we were instructed to low-ball.
Sometimes the interview doesn't tell the story. (I'm thinking of the movie Moneyball and its scenes with the scouts who have no sense of the depth of trouble their team had encountered.) We have had cases where we thought the candidate MIGHT be good and some where we were SURE s/he would be good. And in each of those scenarios, a percentage of people slipped though who were not capable of the level of work we needed done.
We were a high-tech software shop for a maker of industrial real-time control systems. The entire field of "real-time" programming is highly specialized and requires people to think of the process being controlled or monitored. If you can't grasp the operational requirements, we can't use you for our purposes even if some bank or mercantile business would LOVE to have you.
The low-ball plus the concept of probationary employment made it possible for us to make cheaper mistakes. PLUS if the person worked out, we had room to give said person a nice raise at the time we confirmed them in position.
We have to remember this about the job market, though. You are NEVER paid what you think you are worth. EVER. You are always paid what your boss thinks your job is worth. AND there are annual surveys out there to TELL your boss what other people are paying for a job just like yours.
I'm actually pretty happy with my salary. If I worked in London in the private sector, I could double it. But I want to work in local government because I can see that I'm making a difference. This scheme is actually my idea, for the town I live in. It was my report that the Cabinet voted on and I am overseeing the project to build it out. There aren't many jobs where you can have an idea, persuade funders to invest millions, and then be in charge of making it happen.