How can we set up such a system to provide full visibility?
Well, it depends on how you design the system. You could set up readers at a warehouse's entrances and exits, so you could know what arrived and check everything that leaves. If you don't set up readers inside the warehouse, you will not know where within it goods are located. If a solution is designed properly, you should be able to have visibility of things you want to track all the time.
I think the biggest gap occurs while an item is in transit. You can use GPS to track trucks or GPS-RFID tags to track goods in transit. But without GPS, you would lose visibility of tagged items from the time they are shipped until when they arrive at a facility equipped with readers.
—Mark Roberti, Founder and Editor, RFID Journal