Changes of context on your site should only be initiated by user request, or else there should be a mechanism available by which users can turn off such changes. Allowing users full control over changes of context, such as the launching of new windows or submission of forms, will help, in particular, those experiencing low or no vision, cognitive limitations, or intellectual disabilities.
Some changes of context may not be disruptive for users and in fact a number of users may prefer that they be initiated automatically. For instance, an automatic page redirect could eliminate a burdensome intermediate step for users. In addition, those who rely on assistive technologies like single switches might have relatively limited ability to operate your site, and so context changes automated by the system would actually prove beneficial. Similarly, users with low vision may prefer more or less automation of context changes, depending on their needs and the change in question. Accordingly, in some cases it is ideal to provide users with the option to make some changes of context automatic, rather than solely dependent on user action.
This rule has been labeled Level AAA because, whereas WCAG 3.2.1 and WCAG 3.2.2 were geared toward safeguarding users from some types of unexpected changes of context, the intention of WCAG 3.2.5 is to give users complete control over such changes.
For more information on WCAG conformance levels, check out our post on <conformance>.