[Commentor] LC-393 on behalf of Nokia [Working Group decision] Timezone inaccuracies in the client don't normally affect caching since it relies on GMT time. Clock skews aren't specific to mobile devices and should be handled as a case of deficiency in the implementation when specific to a given mobile device. As such, we haven't modified the document, but would welcome a technique on this specific item: link [Commentor reply] no reply from commenter [Comment] 
5.4.15 Cache Headers Proposal for adding a statement [CACHE_CLOCK_SKEW]. Ensure the site will function acceptably without cache, but explicitly set cache headers with long expiration times to allow for clock or time zone inaccuracy in the client.