Agents & Requests--It's Only Polite

I was reading an interesting post by Elana Roth, an agent at Caren Johnson Literary. When a writer receives an offer of representation normally they should let any agents with a partial or full know--just to be polite and also to see if they receive anymore offers. We've been trained by agent blogs all over the blog-o-sphere to do this. But Elana believes that we should even notify those agents who only have our queries who have not responded, especially if we sent them out about two, three, or four weeks before. Seems she tweeted this and it caused a bit of a ruckus. Anyone have a take on this?

Here's the article.