I had a client once who driving a Ford Probe with motorized blets when she was washed off an unmarked low water crossing. The Probe had an emergency release at the upper attachment point, but over time, sun/heat had welded the thing shut. When we recovered the car, it was impossible to get it to release. She manged to pull enough slack into the belt to wiggle out from under it and get out of the car. Manual window drives, thankfully.

She had a truly wonderful story to tell -- she washed 3 MILES downstream from where she went in. She had to duck under water several times to keep from getting brained by bridges that were a matter of inches above the level of the water. She finally washed up against a partially submerged chain link fence, which several bystanders pulled over to get her free.