Asset tag helper and (Google) cache recommendations

Doesn't he have a point? Shouldn't Rails' asset tag helper(s) be
changed accordingly?

http://github.com/eliotsykes/asset_fingerprint

Quote (http://code.google.com/speed/page-speed/docs/caching.html):

Recommendations

Don't include a query string in the URL for static resources.
    Most proxies, most notably Squid up through version 3.0, do not
cache resources with a "?" in their URL even if a Cache-control:
public header is present in the response. To enable proxy caching for
these resources, remove query strings from references to static
resources, and instead encode the parameters into the file names
themselves.

There was precisely a discussion yesterday about this, and we had a
look into that plugin. The plugin looks good to me, and it offers also
hashing which is good for a multi-server setup. I personally think it
would be nice to merge or at least to serve as inspiration to extend
the current functionality.

It would be good to have real numbers about how many hits an app may
save due to cache proxies. You know, to take an informed decision and
to be able to document something more concrete about when some option
would be better than another and why.

Have people working with renamed virtual filenames found any gotchas
in practice worth taking into account?