> My question is how does one avoid this problem if, for example, one is
> making a box/carcase that is not painted?

It took some thought on my part, but I found I could hide the grooves
by changing the tails on either side of the board and then
*remembering* to cut them the way I'd marked them.  Since ASCII art is
too time consuming, I googled *dovetail hiding groove*, and found
these nice illustrations.

http://www.geoffswoodwork.co.uk/dovetail%20sides.htm

Enjoy the weekend,
cur
------------------------------------------------------------------------