I will never let my dog jump into or out of my pickup or anyone elses at any time or for any reason. I have way to much time, energy, and money invested to have something happen to her just because I dont want to take the 4 seconds to bend over and pick her up. I have heard a few stories about dogs slipping on the tailgait, or being tired and mis-judging the height only to break a leg, a knee, a jaw. Not for me. In fact my dog is trained to do just the opposite, she sits and waits for me to pick her up and either set her in the pickup bed or the ground.