He was pretty cool about it, considering the uninstall also removed his saved games without prompting him.
It absolutely prompted him. It would have also prompted him asking if he wanted to uninstall Mass Effect, with no mention of Mass Effect 2. That prompt exists within the uninstaller as we are using the same installer/uninstaller system for Jade, ME1, DA and ME2. It is tragic that it happened, but there were two gates that he would have had to go through before the game and the saves were removed and none of the information presented to him was incorrect. It is just too bad that we never thought of testing uninstalling ME2 with ME1 installed. It just wasn't something we thought of.