Although open captions would not be required, they would also like to hear your opinion on those as well.
The Federal Register has instructions on how to comment:
You may submit electronic comments to www.regulations.gov. When submitting comments electronically, you must include DOJ-CRT 2010-0112 in the search field, and you must include your full name and address. [...] Please note that all comments received are considered part of the public record and made available for public inspection online at www.regulations.gov.About.com Deafness has a great blog post on this topic.