The more I look at how easy it is to sue someone in federal court--and how expensive it is to deal with such a suit, even if you have essentially no involvement--the more clear it is that you would have to be an utter fool to do anything that provides an excuse for a suit. Anything.
Ideally, you would not own a home, or drive a car, but at least you have liability coverage for those items. Some things are hard to avoid--but running a business that helps people is clearly on the list of unnecessary things that open you up to great risk, unless you have a $400 an hour lawyer watching everything you are doing, and warning you about what steps you need to take before do something.
It is a really, really scary country in which we live. I would be curious to know if the situation is this crazy in countries that don't have so many lawyers.
UPDATE: While trying to figure out whether to close it down, I have discontinued the ZeroMotion version of the caster product, not out of fear of lawyers, but because the German-made casters that I used for this turned out to be too inconsistent. The first few shipments were really excellent. Once locked down, they did not move even a little. The last shipment was sloppy, and the manufacturer considers this sloppiness unfortunate but within spec. (Even Germans don't make everything perfectly!)
The number of customers that actually needed the ZeroMotion version wasn't huge, but I was trying to meet a customer need. Now I have to pay the restocking charge to return the half a case of these that I have.