No they don't. If I'm (or anyone lese for that matter) driving or cycling on an unlit rural lane (as are many of the roads round me) and an unlit cyclist comes out from a side road and I (or a.n. other) can't stop in time, due to no lighting, and they are injured or worse, then I (or a.n.other) have that on the conscience for the rest of the natural born, even though it's not my (or a.n. other's) fault. Unlit cyclists do put others at risk. Someone can be cycling or driving in an entirely reasonable and legal manner and through no fault of their own, end up injuring or killing an unlit cyclist. They may even end up injured themselves in trying to take last second avoiding manouvres. It's not about some mass and widespread death & destruction, but it is about a very real risk to others who are not at fault.