I was at the gumball machine until something like 3am central time and saw no one, besides my friend, while there. The people stopped going to get the green bowls surprisingly early. I can't remember the exact time right now, but I think it was fairly desolate by 11pm. I think they stopped completely by about midnight. I could have missed someone, but not many, if any.
I suppose people didn't bother with it because getting killed was so fast and easy. Plus, if you didn't have a rune to the area, it took a l o n g time to run it.
There are not as many of the Green Bowls as there are some other 'vending machine' event items. I doubt the numbers are even close.
BlissMarie