No idea what the law actually says, but this seems like a job for the "obviousness" standard that we've also got in patent law (for better or worse). If you're

No idea what the law actually says, but this seems like a job for the "obviousness" standard that we've also got in patent law (for better or worse). If you're poking at a product to figure out details about it that are "not obvious", and then you build a product with those same details, that's "reverse engineering". In this case it does sound like they were trying to figure out API conventions, and not real engineering details, but that's just my cursory reading.