use of literal 'pi' in cn example (section 4.4.1.1.3)

In section 4.4.1.1.3 the last example is an example of 'pi', where 'pi' is
expressed as a symbol. This notation is not in the spirit of content mathml,
as 
1) if the intention is to refer to a symbol called 'pi', then the
appropriate mechanism is to use the <csymbol/> element instead of using the
<cn/> element
2) this constant is already defined as <pi/>

Since the grammar does not say what type="constant" means, using &pi; is not
forbidden (for all we know, the author's number system could be &pi; &rho;
&sigma;). However, I don't see it that this notation should be promoted by
listing it in the specification.

For completeness, this is what the paragraph I'm referring to looks like:
4.4.1.1.3 Examples 

<cn type="real"> 12345.7 </cn>
<cn type="integer"> 12345 </cn>
<cn type="integer" base="16"> AB3 </cn>
<cn type="rational"> 12342 <sep/> 2342342 </cn>
<cn type="complex-cartesian"> 12.3 <sep/> 5 </cn>
<cn type="complex-polar"> 2 <sep/> 3.1415 </cn>
<cn type="constant">  &pi; </cn>

Kind regards,
Michael McCarthy.