I ride one bike with stem shfiters. Not saying it cant happen, logic and its postion looks like its a possibility. But also there is a possibility that your end up with a brifter in your groin too. There is probably a situation where a bottle cage may end up where the sun don't shine.

I have crashed with my bike that has stems shifters, the shifters didnt hurt me at all it was the pavement the did all the damage.