Please avoid focus stealing

1- I'm writting furious python while installing something; let's say it was Steam;
2- Suddenly Steam installer needs to ask me something, so launches a pop-up;
3- The pop-up steals the focus from my text editor;
4- I don't notice it fast enough to stop writing, and some of my keypresses are captured by the pop-up;
5- One of this keys does something to dismiss the pop-up, with consequences unknown for me: I have accepted or selected something I don't even know.

This is a problem, I think, too obvious to be unsolved in 2013. Afaik, only XFWM has some configuration option about it.

Gala could make a good point here by implementing some prevention mechanism, or a much more sane policy, like:
a- Don't allow focus stealing at all (if something really needs my attention, we can notify it on plank, and/or with a standard notification).
b- Don't allow focus stealing while typing: we already detect whether the user is typing or not, to disable the touchpad in a laptop; if an application needs to pop something up, we could delay it until the user is not typing, using the same mechanism.