This ski season we heard from a significant number of skiers who had serious accidents when the bindings did not release their skis during a fall. Bindings are adjusted to accommodate different characteristics of the user, including experience level and physical condition. Ideally, the bindings will release the skis when needed to prevent greater injury to the skier. Skimag.com has a good article describing the DIN setting on the binding which adjusts the pressure necessary to secure a release, DIN Settings.
But unfortunately, the release of your bindings is not the only release with which you should be concerned – the release or waiver you sign at the time of ski rental also will be a consideration if your bindings fail to perform as needed. In the last two months, I have spoken to at least a half dozen individuals with horrific leg fractures due to bindings not releasing, but each had executed a release with the rental shop and so had no recourse for the erroneous DIN setting or faulty equipment. Remember, signing away your legal rights has consequences.