We're not yet in a Wi-Fi only world, and network cables do have a habit of going missing around the office. So from that point of view we quite like the idea of lockable Ethernet cables, which you can't remove without the custom key.
At $8.75 for a five metre cord, these aren't the cheapest-ever cable we've seen, but you can easily pay more for a standard cable if you don't shop around. Our one concern? It's a universal key design, and the key is only 66 cents -- so nefarious types might not have to work too hard. Still, for venues such as conference centres where cables are easily grabbed, these could make sense.