By default, when you install ArcMap, newly added layers are visible. You can make newly added layer non visible through ArcMap Options (General Tab in Customize ArcMap).
It would be nice to have an option similar to this to make newly added layers non selectable. I frequently add and remove layers while editing and almost always forget to make the new layer(s) not selectable, meaning that when added, the next time I mean to select a feature, I have to unselect all, remove the new layer(s) from the selectable layers list, and select the feature again.
