Mac Authentication - what happens after session timeout

[lc]

Hi,

Why does coova-chilli (SVN 167) not retry a mac-authentication after a  
mac-authenticated session has timed out (or was manually closed)?
Only when the client removes his DHCP connection (during an active  
session) and reestablishes it later chilli tries again to mac- 
authenticate him.

Is this a bug? If it isn't, what are the thoughts behind this behavior?