Trading the adds and deletes works more times than not.
A couple of times per year, it doesn't work at all and you catch a severe beat down, today being a prime example. I got a look when I entered my MOC order, they were paired on a lot with not much of an imbalance.
It is the right trade though, 7 million needed to be bought. When Lehman has an order for some institution to sell million on the bell and walks into the crowd at 3:57, you are dead.
If you were short going into the close, it was pretty lucky, but not necessarily the smart trade. Then again, after looking at my p&l, being long wasn't too smart either, but it is the right trade and I would do it again.
As for the GS trade taking away other good ones, TAP. A and TAP.B both worked very well, and that was a week and a half ago.
The punishment dished out when they don't work deters enough people from "trying that again". No fun to see it print in the hole $1.