Not open gaming, but D20...
A situation came up in last nights game. Our wizard had just cast
'grease' on the floor of a room. My sorceror was in the doorway, and
contemplated zapping the grease with Burning Hands, thus creating
insta-conflagration. I decided against it because we didn't want to burn
the building down, just take out two assassins in the room. However, the
issue of whether the grease from a grease spell WOULD ignite remained
undecided. (The DM ruled 'no', which we accepted, because it would be a
VERY munchkin spell combo, but I wonder if there's an 'official' ruling,
or just a statement of opinion from other D20-ers?)
And this brings up a slighlty more on-topic point for game designers:No
matter how much detail you put in your rulebooks, players will ALWAYS
break the bounds.