Did you know that Bing Webmaster Tools won't let you block all the URLs you want to block via the block URL tool?
If your URL is incredibly important to Bing, Bing will tell you that you are out of luck - find another way of blocking the URL.
@Dingman posted a screen shot of the error he received after trying to block a URL on his site. It reads:
It seems you are trying to block URL(s) that we see as important. We do not support these blocks through the Bing Webmaster Tools, and we recommend you add a noindex meta-tag to your URL(s).
Here is a picture:
I have never seen this error before so I'd figure I share it.
Forum discussion at Twitter.