I have not had a case where I decided to sever ties with a companion due to a rate increase. Granted, most of these increases requested were modest. I also prefer to add a tip so I am sure that has reduced the number of requests for a rate increase through the years.
Of course an escort is entitled to an increase, but you also have to consider the market you are in. Many years ago I was a hiring manager for a company in Delaware - offered a position to a consultant from New York City and had to explain to her that the position's market value in the Delaware market was less than the New York market. She had to take a pay cut if she accepted the role. It was a tough conversation - she did not enjoy the experience. Value should always outweigh cost. Tread carefully.