Google managed to inject "7 to 9" of their honeypots into Bing. In 91+/100 cases apparently there was enough to outweigh the Google results on gibberish terms despite the efforts of 20 Google engineers between December 17 and December 31.
However hand they issued twenty engineers laptops which is more consistent with an ongoing effort than a single afternoon of Bing and beer - particularly when you consider that if there was a single method applied and it was known beforehand, one engineer could have automated the whole exercise.
The inability to accurately measure honeypot injections is a bit odd. As pure speculation, it may be that they were not sure if the methods they used to get Bing to show honeypots number 8 and 9 were legitimate.