Recently the University of California, Berkeley, took down online lecture and course content that it had offered free to the public, rather than risk liability for not modifying them so as to be conveniently usable by members of the public with hearing, visual, or manual disabilities. Harvard and M.I.T. had already been sued on similar grounds.

Now imagine the Berkeley take-down times 10,000 — a world in which private commercial, educational, and non-profit entities alike have legal incentive to de-publish any web content they do not think bulletproof against claims of lack of ADA accessibility. That’s not just imagining. It’s the world we’re looking at as a number of federal courts, setting aside years-old precedent, have begun to accept plaintiffs’ arguments that the ADA applies broadly to the web. As freelance lawsuits against private defendants proliferate, the choice is plain: either act to stop this trend, or expect widening disruption and takedown of formerly free web content.

In a much noted June case against the Winn-Dixie supermarket chain, a federal court accepted the notion that the store could be sued under the ADA because its website was a “place” of public accommodation, like a brick and mortar store. As Frank Cruz-Alvarez and Rachel Canfield observe in a Washington Legal Foundation paper, “the court found that the website was ‘heavily integrated’ and a ‘gateway’ to the physical stores, notwithstanding that the website limits customer participation to acquiring in-store coupons, refilling existing prescriptions for in-store pick-up, and utilizing a store locator function.” Since then federal courts have ruled favorably on ADA-for-the-web claims in more than one other case, including a decision by Judge Jack Weinstein of the Eastern District of New York in a case against Blick Art Materials.

I’ve been warning for a long time that web accessibility has the potential to be one of the most damaging and onerous regulatory initiatives in memory. It’s true that with courts split on the issue there is a chance that at some point the U.S. Supreme Court will take a case allowing to resolve the uncertainty and — if we are lucky — uphold earlier precedents such as that in a 2002 case in which a court dismissed a lawsuit against Southwest Airlines. In the mean time, entrepreneurial lawyers have been filing hundreds of lawsuits against local and national businesses over their websites, many of which settle for money out of court, and on the current momentum will soon be suing thousands more. Millions of existing web presences are uncompliant and easy targets for litigation. The real answer is for Congress to step in.