[psykovsky]

Why not just ask straight away if the user wants to send the message as SMS instead of having to change global configurations?

[micampe]

When iMessage fails you get a notification and next to the message appears a button which pops up a menu with “Try Again” and “Send as SMS”.

http://tidbits.com/resources/2013-10/iMessage-failure.png

(Unfortunately that didn't work for the issue fixed by this tool, since the iMessage never actually failed from the sender's perspective)