Chekov's Spell -- This spell has a two-fold effect. The first is to make the target item almost-unnoticeable to anyone not specifically looking for it. The second is that someone who has seen the item will remember it when they encounter a situation that would be perfectly solved by use of said item.
In a new town for the first time, the White Raccoon Lodge looks like a comfortable place to spend the night. The owner, however, makes sure to explain to you that there is a curfew after sundown and the door will be locked... from the outside. "We don't want anyone being caught out on the streets after dark," he says.
Now that you think of it, all the doors in this small town did have a crossbar on the outside rather than the inside... You wonder what goes on at night...