List it as a Mystery

or make the title say

name of box (bonus box)

but don't indicate anywhere what other box it is attached to, and either put no clue, or make the clue say

This is a Bonus Box. The clue is hidden in one of my other boxes.

or something to that effect...

night writer

Here's an example

http://www.atlasquest.com/lboxes/showboxinfo.html?gBoxId=22067

pre

This is exactly what I tried. Unfortunately this box is actually the third in a series and the name is very similar to the first two. If you look at my logbook, or a list nearby boxes, or do a city search, all three boxes are lined up next to each other. Even with no clues listed for 1 box, you know you're going to find 3 boxes. I think I messed up naming them. Same with a mystery box, it is too obvious from the name that they all belong together.

Any other ideas?

I still say, "Mystery".

Mystery boxes won't appear using Basic or Advanced searches. Or City Searches. You have to specifically look for Mystery boxes... or list every single box in the state. Or look in your logbook.

Most people, I would think, have setup searches with auto-notification for the areas in which they frequently go letterboxing or are within reasonable driving distance. Mystery boxes don't show up in those, which means if you're like me and don't worry about everything else, you won't see the mystery box.

You could post the first two boxes on one day, then wait a couple of days and post the mystery. Maybe nobody will notice... ;-)

Alternately, you could...

...enclose the name of the third box in quotes, such as: "Third Box". This will place it at the top of the listing where it will inevitably appear.

or...

... you could just rename the box!

Either way, there won't be a clue until the finders find the first two boxes, so...

Steve

Give it a different name solely for purposes of logging online, and write that name in the logbook with your special instructions. If someone reads someone else's logbook and sees the true name of the bonus, I suppose they could put two and two together, but there's not much you can do about that.

Quote

Most people, I would think, have setup searches with auto-notification for the areas in which they frequently go letterboxing or are within reasonable driving distance. Mystery boxes don't show up in those, which means if you're like me and don't worry about everything else, you won't see the mystery box.

Not necessarily. I get auto-notification of some mystery boxes.