So, in my current play through I am currently shunned by the Legion. Now I have been shunned by them before but they have never attacked me until now, maybe it has something to do with the fact that I killed what's his face you meet in the ''Cold, Cold Heart'' side quest and then again on the Strip after the Benny reunion. Is there a glitch somewhere? I killed him after the 'Amnesty' offer.

go to nelson (if they let you in) and tell dead sea that you are gunna kill everybody at forlon hope and you will gain more fame..

or just screw it and kill them all

Shunned? You obviously haven't killed enough Legion. They can't ambush you if they are all dead...