And do negotiate with full knowledge of your rights.  Case in point (names and descriptions are modified to protect the guilty):

A friend of mine named “Nancy” who is a lawyer, was contacted by “Joe” because Joe’s blind father was forced to walk without his guide dog and cane through an airport thanks to some “funny” security people.  He had huge trouble, banging into things and people until some nice person helped him.  Nancy was going to advise Joe to insist on retraining and counseling the security people and maybe get a free trip or two from the airline in charge. But then Nancy had a bright idea:  she contacted other lawyers who work with airlines all the time.  That’s when she realized that Joe’s civil right to access to a public facility.  There are also Americans with Disability Act issues and Air Carrier Access Act issues.  So what is the point I am making?  Simple:  things are not necessarily as simple as they may seem and you may be entitled to much more than you thought.  When your rights are violated never aim low and always check  with the experts.