laz232: "A more realistic threat is as freebies at business to business tradeshows."
At $200 per unit? I don't think so.
I think we have a completely different understanding of the economics of trade shows, business and industrial spying / intelligence
Scenario 1: Engineer from target company A (say, Boeing), visits booth of Evil Corp Inc.. Talks to their sales guys, gets shown the new modelling SW / new wiring harness / new hydraulic pump - whatever. Rep from Evil Corp Inc says "hey was great talking to you - here's my card and have this" (hands over Evil Corp mug and cable). This allows for a targeted attack.
Scenario 2: Good Corp - say a company know to be a major supplier to Mil / Aerosapce, places an order of Good Corp branded Lightning cables with Best Price Cables (China). Best Price cables is a front by the Chinese Intel Services.
In qty these doctored cables are 5USD / 10k units, i.e. costs the Chinese Intel services 50k USD to have a great shot at free spying. Good Corp is none the wiser and all the companies that have visited the Good Corp stand are potentially compromised (at the user level).
I have been to a lot of trade shows as an engineer: USB sticks, charge cables, rulers, Bluetooth speakers, MP3 players, mugs, t-shirts. I normally don't take any of that crap on principle - but I have gotten (and used :-o) a USB-A to Micro-USB / Lighting charge cable from Huber Suhner (look them up).