The light from windows doesn't count as light that can give away the Player's position, even though it silhouettes him.
If the Player uses a flash bomb against guards, the guards do not sound the alarm.
The items that can be bought at stores are so expensive that Garrett's thieving would hardly be profitable.
Some torches and candles are lit even if there is no one around who could have lit them.
Garrett is blocked from using glyphs by a seal in Orland's room. Although Garrett r moves the seal, there is nothing stopping Orland from restoring it.
NPCs don't react to such things as arrows passing right by them.
In a briefing for one of the Is signs, Garrett states that most of Captain Moira's crew did not survive the voyage. In fact all of the crew perished.
If the Player puts out lights, NPCs in the area may ask if someone is playing with a light switch - even if there are only lanterns or torches in the area.