Rule 1603-30: Skills

Using a skill untrained, from some other source (like general knowledge, jack of trades, or just being taught by someone on the spur of the moment) is dangerous. A failure of a 1 (20 in classic)    for someone trained in the skill is bad, but not necessarily too bad but for the semi-trained it usually means some kind of serious disaster: a cook might ended up having meat not fully cooked and thus possibly lethal when eaten, or put in poison mushrooms not realizing their harm. Someone chopping down a tree might hit someone with the axe or have the tree fall on someone.  Somrone riding a horse might smash a horse in a head wounding or serously killing it, or cause it to go insane and throw the rider. 
       This does not apply to controled situaton with a decent teacher. A inexperienced cook may left to their own devices prepare lethal food, but in theory their instructor will stop such nonsense. Nor will they give such a novice such a challenge. This would be a case where the novice cook decides to cook for his group because the is the best cook .  . .