Let's think of the two cookies like a piece of cardboard that has been *gasp* torn in half. Probably by a small child in a fit of rage. Or fit of excitement. Or really, any kind of fit at all. The point is...the cardboard is now in two pieces.
But we want it to be in just ONE piece. so we glue it together on it's very thin edges. How well is this really going to hold up against that very small child? Gluing the cardboard together is like baking the two pieces of the cookie together. It works...but only if you are very careful with the cardboard/cookie afterward.
The natural next step is to add some tape across the surface of both pieces of cardboard. If you want it to be REALLY secure, you would add tape on both sides...but let's not get too far ahead of our analogy. The "tape" on pieced together cookies is the icing that goes over the top. You want to plan your cut-out cookie shapes so that the design will allow for icing to cover the cracks/crevices in your pieced together cookies. Let's look at it in real life.
Start by cutting out both cookie pieces.
Use the same cutter or another cutter to remove the piece(s) you don't need.
Put the cookie pieces together on the baking sheet. Gently mush the edges together to "glue" the cookies into each other as they bake. Sometimes gluing the cookies together is enough, if they are interlocked and share enough edges. Sometimes though... you need to add some "tape."
It can be hard to see past all the lines and "Frankencookie stitches" to the design you have in your head. Don't be afraid to draw your icing lines on top of the baked cookie.
See? Now our icing "tape" covers our "glued" up cookie lines and this cookie is solid.
I would have complete confidence mailing these cookies. You can also use the icing as "tape" on the BACK of a cookie that has thin parts like the neck of the margarita cookies.
POP QUIZ!!!
Have you got it figured out? Let's say that it's very important to the safety and security of the world as we know it that you make this very adorable and slightly wonky blue-headed, green-eared guy as a cookie. Would you put it together like example #1 or example #2?
Please say example #2.
Because that would be the right answer.