ISSUE-298: With reference to Eduardo's point about linked stylesheets, http://lists.w3.org/Archives/Public/public-bpwg/2009May/0011.html, we need to review in the light of an earlier decision on images and possibly aslo in light of a recursion problem with link rel=

From the CSS standard, section 6.3, the @import rule:

The ’@import’ rule allows users to import style rules from other style sheets.
[...]
The ’@import’ keyword must be followed by the URI of the style sheet to include.
[...]
So that user agents can avoid retrieving resources for unsupported media types [p. 77], authors may specify media-dependent @import rules. These conditional imports specify comma-separated media types after the URI.
Example(s):
The following rules have the same effect as if the imported style sheet were wrapped in an @media rule for the same media, but it may save the UA a fruitless
download.
@import url("fineprint.css") print;
@import url("bluish.css") projection, tv;
In the absence of any media types, the import is unconditional. Specifying ’all’
for the medium has the same effect.

Conclusion: linked references in external style sheets do have an implicit or explicit media type associated with them. Hence it appears feasible to enforce the rule that style sheets _explicitly_ marked as "handheld" must be transmitted transparently (CT proxies must check for the associated media type). The mechanism is dependent on (X)HTML (i.e. the link element) and CSS itself (i.e. the @import clause). There is no assumption on HTTP (presence of no-transform or otherwise).

Whether style sheets marked as "all" implicitly or explicitly should be handled in the same way remains an open question to be dealt with in relation with the link alternate discussion.