In middle school, the students would ask if the reading assignment to page fifteen includes page fifteen or only up to page fifteen. Clearly the problematic word is "to".
Nowadays for solace I go to the dictionary, which says until means before.
"I'll stay until ten" means that at ten I'm not staying, I'm going. Also, "Till death us do part" is pretty definitive.
Older and therefore more fundamental is till. And one can't discount Till Eulenspiegel.
Thanks for bringing this up, I also have to think twice. Maybe the IDE could have a rollover or annotation, "You know this is the one that means not including
In the REPL, print-tab says,
scala> 1 to 10 //print
scala.Predef.intWrapper(1).to(10) // : scala.collection.immutable.Range.Inclusive
scala> 1 until 10 //print
scala.Predef.intWrapper(1).until(10) // : scala.collection.immutable.Range
So the unnamed default is Exclusive. By coincidence, the unnamed default in society is also exclusive, which is how it maintains its privilege.