Alan, the rating is that it will switch at 6watts. My disappointment is that I never considered that anyone would switch the DC output rather than the AC mains input.
Harry, I know we're talking in terms of AC and it's really impedance that counts, but DC values should suffice.
14.3K @ 230V = 3.7W (approx) which is sufficiently under your quoted 6W figure, so IMO the device is out of spec or needs adjusting.
It's not unusual to switch the low voltage (DC) side of many devices these days. Very often the 'OFF' switch only kills the output, not the supply. It allows the manufacturer to skip round heavy safety insulation for high voltage devices, making the overall cost (to them) cheaper!
I realize that you're not too worried about the small current consumption, but the inconvenience of not being able to use the master/slave device really is an issue and the supplier of the device should correct it.
Personally, I'd demand a refund on an out-of-spec device, then go look round the thrift stores/garage sales or perhaps one of the online freecycle schemes, for an old shop vac with an AC outlet. They're often discarded because the armatures or bearings have failed, leaving a useable master/slave switch. You could probably get a beaten up device for not far off $5.
You don't need to be an electrical genius to work out where the power goes in and comes out and connect it according to your needs.
The only issue for you would be finding a 230V device, which I guess would be more rare in the USA?