Does opening the 2008 Honda Civic Coupe's moonroof make the roof easier to leak water from the outside to the inside of the car?

Does opening the 2008 Honda Civic Coupe's moonroof make the roof easier to leak water from the outside to the inside of the car?

No… All sunroofs are built to leak water. The "seal" is just to stop direct water pressure form entering. There's a tray inside the sunroof that collects water and has drain tubes at all 4 corners that drain the water down tubes in the pillars and comes out by the tires.