<selectMany> and radioGroup - a wise combination??

I was looking at Chapter 7.6 where an example is shown of the <selectMany> 
element/form control in combination with a possible visual presentation as a 
radioGroup.

I would like to ask the WG to consider whether this is a wise combination.

Over several years the implicit metaphor of radiobuttons, at least in the 
interfaces that I am familiar with, is that the user can choose ONE from 
several. If one option is selected any already selected option is deselected.

To provide, as Chapter 7.6 seems to suggest, a radioGroup with selectMany 
will violate this assumption which many/most Web users will implicitly 
expect. Is there a setting, that I am not aware of, where the 
selectMany/radioGroup combination is already generally used?

I think that the combination is likely to have significant potential for 
confusion.

Andrew Watt