While it's easy to say the site must legally be 'accessible', the problem I've encountered is that there is apparently no legal standard for 'accessible'. Section 508, WCAG, etc. do not have US caselaw behind them that actually identifies them as such.
From a practitioner's viewpoint, it might make perfect sense to target WCAG, and possibly consider anything less 'unaccessible'. However, from a legal viewpoint - which typically doesn't acknowledge any obligation or liability without precedent - it's a very different situation.
I'm curious if these tort cases can set that precedent, and clarify things for the lawyers.
In general courts look at standards IF you point the judge to it. The judge will look at the standard, and if it looks reasonable will accept it, thus creating precedent. If your website obeys a standard the other side needs to prove the standard isn't enough to meet the law. That is if you meet WCAG the judge will probably default to considering it a bug in the screen reader - putting the burden the screen reader to show that the standard is not enough for ADA, not only is this a higher bar, but the judge will generally cut you some slack for trying.
The above assumes there is only one standard. Standards bodies (ANSI, ECMA, ISO) often accept multiple competing standards. This happens when they are not aware of the other standard, or when they believe the standards can compete (C++ doesn't prevent you from creating an ISO standard for a different programming language).
Companies will often try to get their internal process encoded into a standard for this reason: it documents something that can be brought to court with more weight than something they came up with: if you sue latter the judge will ask if you care so much why didn't you get involved with the standards process when the company created their standard. Since part of becoming a standard is you have to take input from others this is somewhat reasonable.
The above is a US perspective from not a lawyer. Other countries have different rules. Talk to a local lawyer if you need legal advice.
In general US civil court judges will cut you some slack if you can demonstrate that you acted in good faith and made reasonable efforts to comply with the law, even if you are technically violating some rules. This applies to most sections of civil law, not just web accessibility.
From a practitioner's viewpoint, it might make perfect sense to target WCAG, and possibly consider anything less 'unaccessible'. However, from a legal viewpoint - which typically doesn't acknowledge any obligation or liability without precedent - it's a very different situation.
I'm curious if these tort cases can set that precedent, and clarify things for the lawyers.