I had a thought…So Marinette doesn’t even entertain the possibility that Adrien could be Cat Noir because they act so differently. But Gabriel saw the ring and instantly started suspecting his son of being Cat Noir, despite the fact that he’s seen Cat Noir in action and knows how different they seem.

Which means at some point Gabriel thought to himself, “So if my sweet, calm, studious, obedient son was offered the responsibility of becoming a superhero and wielding a powerful and dangerous artifact; would he use it to become a leather-clad hooligan who cracks terrible jokes and flirts like he’s in a cliche shoujo anime?” and he concluded “Yes. He absolutely would.”