Load shifting picking up the back end of a pickup is an almost impossibility unless the operator is being flat stupid. About the only load that will hang up as you tip is sticky mud, or a load that froze in the trailer. Either can be handled easily by installing a vibrator on the dump bed.
Anybody who continues to tip a hung load expecting gravity to discharge it is a complete fool and shouldn't be driving so much as a bicycle. If the load isn't dumping at 30 degrees of tilt, you stop tipping and find out why.