I was afraid of that, and just before you commented I had updated my post to mention that possible problem.
I guess to implement it you'd need to do a literal descending price auction a la Gnosis, which I wouldn't be so quick to support.
Thanks for the quick answer.
hey @biophil, just noticed this on github and posted about it in the new EOS slack. thought you may also very much appreciate hearing about it! :D
Actually, just wrote a post about it too: "EOS Token Sale Smart Contract May Offer BUY LIMITS after all!"