I tried the Target tracker a couple of times - it has failed me both times.
On Wednesday night, it showed there were 32gb models in stock at a Target near me, I almost drove out there, but decided not to waste my time. Yesterday at lunch, it still showed they were in stock, so I drove over there. They had no black models in stock, only two 64gb white models. I passed on them and went back to work. When I got back to work, the Target tracker showed the 32gb model was out of stock.
This morning, the Target tracker said there were 32gb models in stock at the same store, so I swung by at lunch again. This time, there were no iPads on the shelves, but I checked the tracker with my phone and it was still showing up in stock. I asked someone and they checked in the back and with the days deliveries, but found none. The Target tracker is still saying available at that store, so it must be incorrect.
I'll probably keep checking the Target tracker since I don't work that far away, but I don't know how reliable it is. Lots of people in the Macrumors thread have had luck with it.