Is creating a unit a 'user' function?

Working on siunitx version 2, I’m confronted with a slight problem. Currently, the macros used to manipulate units are called

• \newunit
• \renewunit
• \provideunit

which follows the LaTeX 2e \newcommand, etc.; the same is true for prefixes and so forth. These names were probably not the best choice: for example, biblatex also has a \newunit macro (although there is not a clash, luckily).

I’ve been thinking of better names, but I’m not sure whether these should be document level (all lower-case), or design level (mixed upper-case and lower-case). Some ideas:

1. \DeclarePhysicalUnit (create without checks)
2. \NewPhysicalUnit (create with checks: would require \RenewPhysicalUnit, etc.)
3. \NewUnit (as 2 but shorter)
4. \newphysicalunit (as 2 but document level)
5. \createphysicalunit (is ‘create’ better than ‘new’?)
6. \createunit (avoids the confusion with biblatex)

You’ll see that I’ve not included ‘SI’ in any of the above: it looks odd, and of course you can create non-SI units anyway. How do other people see this?