If you are using a sacrifice or escape branch, you do need to be concerned about scars. There are some different options
1) Use multiple sacrifice branches and remove them before they become so large that they will create large scars
2) it is easiest if the scar is made on the back of the tree. That way it doesn't show from the front.
3) Sometimes the sacrifice branches can become features. Stubs left on juniper and yew for example really enhance the appearance of a tree that has grown and died back several times. They would need to be carved skillfully and obviously tree species that normally have deadwood features would be more appropriate. This wouldn't be convincing on a maple, or azalea but could work well on a flowering apricot or a pine.
4) Read about how to heal wounds and take appropriate steps. There is a good article on the <a href="http://www.treebay.com">TreeBay.com</a>
site on healing wounds in the articles section
Regards,
Matt