I mean it's always a little bizarre when the default unit used to measure something is dimensionless. Why not set a default (like STP) that's assumed to be the baseline unless otherwise specified? It would be like if Celsius had no reference point and every time you said water boils at 100 degrees Celsius people came out of the word work to smugly correct you "Only if you first say 0 degrees C is when water freezes, which you can't assume. What if 0C is actually absolute 0?"