I agree that it seems like an odd practice, could be a mental artifact from usin...

I agree that it seems like an odd practice, could be a mental artifact from using the scala interpreter. When you create objects in the interpreter w/o a name it is starts enumerating at res0.

  Welcome to Scala version 2.7.5.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_15).
  Type in expressions to have them evaluated.
  Type :help for more information.

  scala> "hello"
  res0: java.lang.String = hello

  scala> "world"
  res1: java.lang.String = world