>> Which is why I protect the initialisation with #if PY_VERSION_HEX <
> 0x03090000
> 
> It is your specific case.  We can not assume people do it, or even you
> never forget it.  So this is not the "right thing" we can recommend to
> all users.
> 
> Once you or other people suppress the deprecation warning and forget
> the protect, compatibility issue happen again.  Why such dangerous
> option is needed?

If I fail to protect against using a feature when it is no longer 
present then it's a bug in my code and it won't compile. Providing a 
deprecation warning gives me some notice that my code needs to be 
changed. That is helpful but not strictly necessary as I will soon find 
out when testing against the new version. There is nothing "dangerous" 
here.