You're paid to work those hours, and I've no issue being tracked for those hours (or slight deviations ... for instance, I work 7:30 - 4:30, but same basic concept)
Hell, I'm already tracked via badge. Most of the doors in my building are locked, and opened via my company badge, which is unique to me. While this doesn't give them exact data on every move I make, it will clearly show what time I arrive in the morning, what time I return from lunch and any time I move into a different area. Anecdotal, but I probably badge through a dozen or so doors per day, which should paint a fairly clear picture of my activities, if anyone cared to look.
And that's fine with me. I'm on their hours, at their facility. But when the company wants to start tracking me after hours, on my vacations, during my sick time, etc ... well then they can fuck right off. But if they want to keep better tabs on me during the hours I'm in the office, I see no harm in it.