In another thread on this forum (Acoustic Cloth) David Martin describes a neat enclosure based on the smallest "Really Useful Box" (0.07 litre). There is likely to be some variation between AudioMoth units but the width of this box at the top is marginally narrower than the overall width - including protruding switch, USB socket and SD card - of the two AudioMoths I have here. Worse, the box narrows towards the base so there is a serious risk of breaking off the switch tab. I believe future AudioMoth boards will be modified with a cut-out to protect the switch but in the meantime you would be well advised to find a slightly larger box.
I had already tried to use one of these boxes as an enclosure and only discovered this problem the hard way when the switch tab did indeed break off.
Should this problem occur then it is reasonably straightforward to perform transplant surgery on the switch and replace the broken contact assembly, without having to remove the entire surface mounted switch from the board.
I'll post details and a photo in another post on the Device Support forum, where it may be more obvious.
Edit: Apart from breakage of the switch there is also a risk that the SD card can accidentally be released. If this occurs, not only will you lose the data but the card is likely to be ejected at great speed, and possibly lost, when the AudioMoth is removed from the box.
I do add caveats about the box being tight in my description. I have not found it to be too small but there is the risk of releasing the SD card (Yes I have done this) and the switch can be tight. I don't push them into the boxes so don't suffer from breakage.
My thoughts are to move up a couple of sizes (to the 0.2l box) and use a foam insert to hold the audiomoth. This will also help to reduce mechanical noise on deployment.