I really hope that some lessons have been learned...but I doubt it.
Actually, I think quite the contrary. The DJs were in the wrong in the first place, but actually expected the phone to be put down, so they were (from what I have read) surprised they did get info.
The death of this nurse is a tragedy, and I'm sure we all are thinking of her and her family. It does seem quite difficult to understand, because the suggestions are that she was not being disciplined but supported by the Hospital (though clearly it was embarrassing - for her, the other nurse, and the Hospital - but at 5:30 after several hours on shift, I'd hope they considered it what it was... simple human error).
As for the DJs, yes, they will have this on their conscience, but they had already made some form of apology, and one would have hoped that would be an end to it. This tragic turn of events will not only shock them and their station management, but prank calls under the spotlight at any station, and should assume stations will reconsider, and not do prank calls where they might think there's a chance of someone being disciplined for falling for their prank.
So, so, sad that someone doing an important job (especially compared with being a radio DJ) has been lost from society. Can only imagine what was going through her mind. RIP Jacintha Saldanha.