There is no control of references - SEF URLs:
1) standard references of a look "site / extreme category/the goods".
2) long references allow to indicate a full way to the goods: "site/category/..... / category/the goods".
3) short references assume placement of one goods in several categories. In this case the reference will look like: "site/the goods" and you will get rid of duplicating references (categories aren't displayed).