I think its a perfectly valid question. The reason Target hires so much is that the turnover rate on employees is high, that and they want to keep team member hours low to prevent them from having benefits.
not everyone interviewed will get hired or if they are will drop out before orientation. We add people when people leave if needed. At least for the backroom the seasonal hires start 2 or 1 week before black friday. Which to me is always pointless because by the time they figure stuff out they are done.