Halo 2 wasn't properly tested; it had had 3 laps from 2 drivers, and 1 of them had (possibly minor) problems using it due to visibility and comfort. Also, one wheel test appears to have been translated to "invulnerability to large, heavy objects", even through a Wurz/Coulthard Australia 2007-style accident (or Alonso/Grosjean Spa 2012 or /Raikkonen Austria 2015) would likely break a titanium bar in a way even the steel bars used on Halo 1 would not (due to titanium's strength being directional). I am glad about this, as I think Halo 2 in its current form is more dangerous than doing nothing, and that the FIA would not have found the implementation method that avoided lawsuits. A better-researched version is something I could see being put on an F1 car, but not until it's ready for use, please.