Wiki advice on running getmail on INBOX access - how does that work?

[c128 mail]

Hi,

I'm currently running getmail in a cron job every 2 minutes, so I was 
quite intrigued by this on the wiki:

http://wiki2.dovecot.org/HowTo/TriggerGetmailOnIMAPAccess

Thing is - I couldn't see how it would work and, when I tried it, it 
didn't work (at least not for me).

It details using incrontab to monitor /home/username/.maildir/cur in 
order to trigger getmail.

However, "cur" won't change unless populated with mail...as an initial 
result of actually running getmail?  Seems like a chicken and egg situation.

I reckon I'm missing something fundamental :-), but what is it?

Ta.