I have seen these sockets used in a non-listed manner, that is, a turn-knob suspended by a piece of zip cord. [Linked Image]
These DIY jury rigs always end up in the trash if I have any say in the matter!

In fact, one really bad house I worked on had a basement that was completely lit with a rat's nest of extension cords and turn-knobs.
Needless to say, the basement was rewired with porcelain lampholders and proper boxes and romex.

Peter