Well "so much" seem like quite strong words ...
For one, i must admit that i have no idea how many barrels of wich flamable material is in game curently ... but i honestly doubt its more than, lets say 50 for example.
That dont sounds like so much to me ... especialy, once you remind yourself that ingame map is obviously not 1:1, since it would take Goblins to litteraly 5 minutes walking east to find Druids grove.
![laugh laugh](/images/graemlins/default_dark/laugh.gif)
And yes, i know that in Goblin camp there is room that is STUFFED with explosives ... but that have story-wise reason.
![wink wink](/images/graemlins/default_dark/wink.gif)
So ... that "certain encounter" you are talking about is? O_o
Bcs i can remember only Goblin leaders ... and maybe Cambion General (still dont remember his name) in tutorial ...
And in both cases you need to drag Barells from conciderable distance to use them in my opinion. o_O