Legend of Drizzt "Cavern Tile" triangle color
When you place a tile with a black triangle you are also supposed to draw an encounter card during the Villain phase, so tiles with black triangles definitely can be more dangerous than those with white triangles.

From page 6 of the rulebook (right column, top of page):


  Triangles: Each tile features a triangle. When you place a new 
  tile, the triangle points toward the unexplored edge of the tile 
  it is attached to. If the tile has a black triangle, you draw an 
  Encounter card during the Villain Phase of your turn.


And from page 8, Villain Phase, point 1:


  If you didn’t place a Cavern tile in your Exploration Phase, 
  or if you placed a Cavern tile with a black triangle, draw 
  and play an Encounter card.