Heated Rivalry AU where the relationship reveal happens because David Hollander's phone gets hacked and approximately 5,000 pictures and videos of Shane and Ilya being cute (both together and individually) get dumped onto the internet.
No accusations can be made about them throwing games for each other, because there are several videos of them being super competitive about absolutely nothing. For example, one of the dumped files is a video of the two playing Monopoly (filmed discretely from a hallway). They look about ready to murder each other. And then, off-screen, Yuna's voice - in a Mom Voice TM, of course - calls, "Boys, you better not be doing what I think you are!"
Ilya says, "Nyet, Mama," at the same time Shane says "No, Mom!" And in perfect sync they hide evidence of the game, not a single movement between them wasted.
There's also a video of them trash talking each other for being slow as they race to put away the most clean dishes from the dishwasher.
It's a whole genre. Play-fighting as they bring out a measuring tape to literally measure who shoveled the most snow from the driveway, bringing up hockey stats as they argue over who deserves to hold the tv remote, etc.
And, of course, Ilya isn't upset at David for the whole incident. Ilya is crying, though, because it's clear from looking through the photos how much David absolutely loves Ilya. It's so apparent through the captured moments how much David adores his second son.