git send-email should always ask for in-reply-to

Hi,

i currently have the problem that, if I set sendemail.from and sendemail.to in 
git-config (from global and to project-specific but that doesn't matter) git 
send-email doesn't ask me for a in-reply-to message-ID. I set these 2 config 
options for convenience. But i also want to specify a message-id after calling 
git send-email to get a proper thread on the mailing list.
I dived into git-send-email.perl and found $prompting which is only != 0 if 
$sender or @to isn't already set (lines 672-685). On line 706-709 there are 
some check whether $initial_reply_to should be asked or not. If $prompting is 
sitll 0 $initial_reply_to will not be asked.
In my opinion git send-email should always ask for in-reply-to. I know there 
is --in-reply-to option but this keeps me from using the git command from 
shell history as i have to modify the parameter each time.

What do you think about it?
Best regards
Alexander