The rules in YSlow and PageSpeed are general rules. I imagine that, if the developers were to incorporate logic for every known, appropriate exception, even on their own sites and services, the project would be untenable in terms of manpower, let alone code and performance. The point of these tools is to offer recommendations. If you can do something about the individual recommendation, then do it. Otherwise, if circumstances prevent it (e.g., it's out of your control or it would break your application), don't.
Jeremy R. Geerdes
Generally Cool Guy
Des Moines, IA
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