Since when is this possible?

O.o how xD ?

MGO physics fail. It's possible since forever. xD Basically, you know how sometimes when you run into a empty box your character climbs on it and it breaks under his legs? It's the same thing with randomly spawned box on the roof, you run into it, your char get's on it, but since the gap between roof top and box isn't too big your char simply steps up and box doesn't break under your legs.

I'm seriously being Captain Obvious now. Haha.