Well I have seen normal stick packs broken in crashes, but there is a simple way around that, and we do it with our 'normal' packs and also with our Lipos as well.
The basic idea is to strap the pack in with a big rubber band. We use bicycle inner tubes and cut them into strips and they hold the pack in. It makes it VERY secure and supports it a lot better.
Over half of us at rc-mini now use Lipos all the time....
Check the pic for what I mean.