I agree with JSWolf. *gasp*
If they are all willing to share an account, that's their business. Chances are they'd just swap paper books within the group anyway.
Otherwise, unfortunately I do have to agree with what some of the publishers are saying. Due to the cost of an ebook reader, so far most of the "ebookers" are likely to be on the high end, and competition for leisure time hasn't fundamentally changed. It also seems like the question isn't as much volume as revenue; buying more books may not be great for the publishers if it results in a net loss of revenue.
That said, I do think the publishers need to be prepared for the growth of ebooks. Hype is high right now, and I don't think paper books will permanently go away, but I do think that increases in ebook sales are very likely to come at the expense of paper books sales, especially hardcovers. I'm not sure that digging trenches will turn out to be the best tactic.