USB Cables witha Loop

loop? maybe you are referring to a ferrite coil. if so, its there because the numnuts in Europe want you to add something useless to any cable that might radiate high frequency noise. its not needed in the us, so possibly the ones you have seen were destined for sale in both locations.

Really? Something wrong with the ether in the US?

Al Gore know about this?

so possibly

Is that the cylinder on some cables? I always wondered what that was.

Right.

Sometimes the cable goes through, sometimes loops around.

It's a ferrite bead. These pups are used to attenuate common- mode radiation from the cable (they have no effect on the signals within). Their use has nothing to do with which side of the pond one is on, rather how the equipment operates. The placement of these blobs isn't random either. There is art to this EMI stuff!

the only ones I have seen that have them seem to be those labeled for use in Europe. maybe a coincidence, but I do know that some I saw a few months ago said right in the instructions hat the ferrite coil should be added only if CE requirements had to be met.