I have a prototype that inserts a fairly weak ISM band RF signal (HF/VHF) as a way of detecting a connection between two metal objects without there being a DC return path (Ideally I would use TDR but I can't do that on my budget at home).
I don't think it would be classed as test equipment (it's not a toy but it's for sports - the inside is basically a very narrow band Vector Network Analyser combined with an equally limited spectrum analyser/Software defined radio), which - if I understand correctly - grants an exemption.
It would be sold just as the sensor(à la test equipment), would it be tested as sold or would it need to be EMC tested as it is intended to be used (I'm not yet sure whether this particular example would pass or not in the sense that it isn't a radio transceiver but that's's a different a question)?