There are some reports from a member on SEW Forums that says he is experiencing sites who initially get indexed for the first time going straight into supplement results. I can't say I see this as being a good sign in anyway. He goes into how he has watched several sites for a few indexing cycles and noted that they are getting dumped into the abyss of supplement results index. Some people are saying that if you launch a new website and your pages go into the supplemental index, its not Google, its your pages. Marcia, a moderator at the forums says that new sites no not go into the supplemental result index and that it has to be a result of something else. Some people are disagreeing with a few other members jumping in saying that it does indeed happen, and for some site they get into this index before going into the true index of results. In my opinion it could be related to pages with no links to them that get this effect when first indexed. The thread meanders on with feedback and disagreement about certain issues. If you are experiencing this, you might want to jump in, otherwise it looks like new sites do not first go into the supplemental index automatically.
Discussion at SEW Forums - New Sites & Supplemental Results