Objections against CP for ISSUE-130
The change proposal cites GMail as an argument to support layout tables, but Google's opinion is that GMail's use of layout tables should be considered a bug. We do not have a problem with it being considered non-conforming.
The change proposal says that a reason to allow layout tables is that not allowing them would require ATs to implement custom heuristics to detect layout tables. However, this is both false and not an issue:
- It is false because such heuristics would be required regardless of the authoring conformance criteria, as they are needed to best serve the user's needs for legacy content anyway, and
- It is not an issue because ATs already implement such heuristics anyway, so there is no extra cost.
The change proposal assumes that all accessibility-sensitive UAs are UAs with ARIA-supporting ATs based on platform accessibility APIs. This is false. Any UA that does not use the author-provided style sheets is affected by the use of layout tables, including text-mode Web browsers, speech-CSS browsers, and browsers that let authors disable author styles.
The change proposal suggests that we should design authoring conformance criteria based on the cost of porting existing documents and applications to the new conformance criteria. However, this is misguided. Conformance criteria should be designed around best practices; legacy documents are already written and therefore would not benefit from improvements to QA tools such as validators in any case.