Of course she can. It's static. She doesn't want and I understand. She's signaling their clients an standard call to say "I think you already have read this, at lest ask me first when this changed the last time".

If you choose to run a poorly implemented rss feed and not scale it cheaply you lose any sympathy from me.

So long as you know what If-Modified-Since is, and use it, you can have all or none of the sympathy you want.