My electric stove is by necessity fireproof, as is my girlfriend's gas stove. If you have a combustible stove (!?) then the sink is a better idea, like you say. Or possibly the bathtub. Or the back yard. This is less of a concern for me because my house is not made from combustible materials.

I have in fact had a raging alcohol fire on top of another gas stove due to spilled fuel (for reasons much more stupid than cooking over a camping stove in my kitchen). Things stored above the stove started to burn (more stupidity). But because my stupidity didn't extend to using something like gasoline or lighter fluid, a cup of water instantly extinguished the blaze. Now I have an ammonium phosphate fire extinguisher in my kitchen. You should too.