Aw dude, let them find out for themselves that Goffrey fucks his own mother and dies of GoT AIDS. :P
Oh, and now that the cat is out of the bag, Robb Stark asked for it. If you didn't know that the Freys were gonna whoop his ass as soon as he married someone else, than you weren't paying attention.
There are 2 ways to get killed in GoT. Make dangerous enemies and put yourself in dangerous positions by trusting the wrong people.
The Starks, imbeciles that they are, tend to do both and frequently. That being said, it should be no surprise they seem to find the afterlife sooner rathrr than later.