I'm the person who sends the cables and the returns label.

The drive cables are worth quite a bit (double figures) - therefore I'd like to collect back as many as possible, although more so when we throw them back at the supplier, there might be enough to hurt someone

Since I'm asking people to pay for the postage, I arranged for returns to be collected at the US office to keep the cost as low as possible. You are under no obligation whatsoever to return the cable - it is purely a voluntary thing. Less than half of customers actually return cables.