Responding to Grumpy Dice’s comment:
A conundrum for me is whether a party in a dungeon using light should have a chance to surprise monsters. I thought the Moldvay Basic text had a statement about this, but I couldn’t find it just now. Practically, it seems unlikely that a party with light could surprise monsters if there are no existing lights in the dungeon. Doors do give the opportunity for a party with light to achieve surprise provided it is broken open on the first attempt or a lock is picked.