“Infamous” used in a positive sense?

I have found at least twice the adjective “infamous” used, apparently, to mean “very famous”, rather than its actual, opposite meaning, both times in non-humorous texts:

The first, a historical essay about ancient Spartan lawgiver Lycurgus:

At some point between the late eighth and mid-seventh century BC ... a new constitution came into force in Sparta; known as the Great Rhetra, this constitution was, by the fifth century BC, associated directly with Sparta's infamous lawgiver Lycurgus...

And the second, a popular science article about the Goodyear blimp:

3 June 1925: The infamous Goodyear blimp first flies. These would go on to be a regular part of sporting events in the US.

Is this a new use of the term? Or were those most likely plain oversights?

If it matters, both texts are by British authors.

Solution 1:

I would guess your passages both use infamous in the context of notorious.

Neither the blimp nor the lawmaker were uniformly good. In fact, every time I saw the blimp, I found it to be a distraction and feared the whole thing exploding.

As for Lycurgus, Wikipedia lists him as responsible for the "military-oriented reformation of Spartan society." I would hardly call this virtuous beyond a doubt.

I admit it's a stretch, but the usage of infamous appears to exhibit a pessimistic view of your two examples usually referred to in a positive light. But the authors are taking a minority opinion and apparently drawing a conclusion based on the negatives. As such, neither an oversight nor an alternative usage--just a stretch.