The last remaining issue in the Sieve variables draft

Hi group,

I would like to solicit some comments on the last remaining issue in the 
Sieve variables draft.
The latest version of the document prohibits all numeric second (and 
lower) level namespaces, e.g. a variable name "foo.1.3" is not legal.
My personal opinion (chair hat off) is that we should allow for such 
variable names, just in case we later on decide to allow variable names 
based on MIME part numbering, or something similar. Does anybody have 
any opinion in support or against this change?
Alexey