(random s5 finale musings) tbh I don't think Marinette chose to keep The Secrets™ from Adrien because Gabriel asked her to. I feel like Marinette keeping secrets like that is so consistent with her character; she hates giving people bad news, she hates rocking the boat, she hates upsetting people, she always chooses to keep any 'controversial' information to herself for as long as she can get away with (examples: bubbler scarf, telling Queen Bee she was benched, confessing to Adrien, warning Chat Noir about Scarabella or Rena Furtive, never told Chat Noir about Chat Blanc, etc) that I just totally believe she would've done it either way. She was even already having nightmares about Adrien hating her for finding out she defeated his father, so I feel like Gabriel's request was moreso giving her a go-ahead than it was a primary deciding factor, yknow?