Caution about jump starts

Hi: This is actually connected to a previous post, but I wanted to make sure folks read this so I'm making a new post here.
My partner's Jetta TDI battery died over the week he was gone and we tried using the Prius to jump start his car. The Prius manual does not explicitly say DON'T DO THIS, and has a diagram of how to hook the cables up. The manual presumes, however, that it's the Prius getting the jump start, not giving one. Anyway, nothing happened.
I learned from other distinguished posters on this chatline, that I could have damaged my car and that the Prius is not designed to be a power source in a jump start. My sense is that if this action would have a high probability of damaging my car that there would have been a precautionary note in the owner's manual.
That said....my partner had his TDI towed to his repair shop where the battery was recharged. The mechanic said that most new cars SHOULD NOT BE JUMP STARTED because you can fry the computer. The batteries need to be slowly charged using "shore power" rather than being rapidly charged as they would be using a jump.
I think both of us were lucky. The mechanic told Lyle that a woman customer of his fried the computer in her Mercedes by trying to get a jump start from someone....5k!!
If any of you have experiences related to this, I'd be glad to hear. I'm thinking of ditching my jumper cables in the garage instead of carrying them in the car, just to avoid the possibility of doing serious damage to mine or someone else's new car.
Bob