They touch on it a bit more in the books- once a guest has eaten with you, their protection is guaranteed under your roof. Basically what the Freys did was in extremely bad form. And broke a ton of laws/customs etc.
I've been waiting all season for this to happen. I think HBO did it justice. These books are very dark, and very violent. Honestly I would have been upset if they would have watered it down.
this exactly xD. though if you want to be "technically" fair, it was pretty bad form that Robb was promised to one of his daughters and then found someone else. especially when they so needed Freys men, I thought it was a bit bold of Robb to say "if frey cooperates" when he was talking with Cat about his plans.. i mean if he expected someone like frey to cooperate you dont dishonor him. xD
I mean i cant help but think that NONE of this would have happened if he had not perused things with the other woman. lol... the whole time they were talking Edmure into accepting Freys new terms. i was thinking... oh Robb this is not going to end well.. there is NO WAY walder frey is going to be satisfied with this xD even if it WAS his idea lmfao.
im pretty sure that Walder justified the wedding as setting things even.