While this topic is almost an exclusive of USains, I appreciate it being brought up in this (work related) forum.
I feel pretty strongly about this. Not because anyone in my family has ever had any sort of 'chronic illness' but just because of my own thoughts on what is correct, what is plain wrong, why we pay for insurance in the first place, and how I feel sure that insurance that is part of your compensation package is supposed to work for everyone's benefit (not just the young and healthy and/or the old and corporate ownership).
How "much" health insurance -you- (or your family) use should NEVER be considered during a discussion of work related performance, and should not even be allowed as a topic of discussion, any more than race, age, religion, political party affiliation or nation of birth and I am pretty sure, in fact, is covered under "HIPAA" as a point of confidence that the insurance company may not share with the employer as identifying anyone in particular.
We all have to recognize that we do have an obligation to each other and everyone else not to waste precious and limited resources, of which health care providers time (just like all of our time) is most assuredly limited, but if someone in your family suddenly needs health care (that was already paid for in your compensation package), it should not ever come into the thought process that it might effect my performance review if someone needed a $100,000.00 USD operation to save their life or to be able to return that person to a productive individual.
What is the reason we pay for health care in advance as part of our compensation packages, if it is going to be "graded" on our ability to not use those same services when we NEED that specialized care (not -want- to flirt with a nurse, or don't -want- to bother clipping our toenails).

Ponykilla, has this happened to you, (?is it in writing?) or is this just something that you have considered?
Florida's Office of the Insurance Commissioner and the NLRB (national labor relation board) and the Office for Civil Rights of Dept of HHS , [the feds] may like to hear your side of the story, and see any documents you can provide to back up the facts, since I am pretty sure this was against US federal and Florida state law 10 years ago, I just don't know if they changed the law, but I would be surprised if they did.