It would... if you're willing to just let the thing draw up to 0.1W all the time, and fail catastrophically if anything goes wrong with the zener or the supply is more capable than you anticipated (i.e. you plugged into a PoE jack by accident). This is a very bad idea.
It would... if you're willing to just let the thing draw up to 0.1W all the time, and fail catastrophically if anything goes wrong with the zener or the supply is more capable than you anticipated (i.e. you plugged into a PoE jack by accident). This is a very bad idea.