Actually there WAS a huge increase in the volume when the company name/symbol changed. It was spread out over 3 days -- the 3 days that a short would have had to cover -- so it was not as obvious. But we had had about 200k average volume and it spiked to much, much more -- my memory says close to a million on a couple of those days but I'm too lazy to look it up
I remember thinking at the time that there were 1.5 million shares more than average traded in those three days.