I'm just looking at it from the street side. Figure the outlet carries say...4 of each the iMac, Mac Mini, Apple TV, Macbook, Macbook Pro, 2 Macbook Air, and 2 Mac Pro, along with say 50 iPods of various flavor and maybe 20 iPhones (I've been the manager of various retail places in the past..it gives you an idea of the average consumer base).
If I were to break into the place, the phones would be the last item I take, as the serial number is instantly traced when the buyer goes to get the phone activated.
The iPods and the computers, while having serial numbers, will be sold on the street, via EBAY, Kiji, and Craigslist (if they are intelligent they won't sell them nearby or all at once), and people looking for a steal won't so finicky on where it came from.
Either the individuals that broke in went for the phones for a reason I honestly cannot think of right now, or they really were just that stupid..