As a GM, I re-skinned Rogue Trader into Firefly for a one-shot I was running for a some local gaming events/conventions. Also, I'm a GM who rolls in the open, so it's clear there is no fudging.
All 3 times I ran it, as the aggressive pirate vessel that was attacking Serenity with missiles, I rolled critical failures. Specifically, perfect 100s on percentile dice, which on the appropriate table indicates the missiles blowing up in the tubes on launch. That guaranteed enough damage to cripple the weapons systems of the ship - and in 2 of 3 cases, doing enough damage to take the ship out of combat entirely when the rest of their ammo went up, taking the ship with it.
Once, eh, it happens. But 3 times, the same game, the same exact place? Senor Murphy was having a laugh, I'm sure of it.