If you've made an NCR playthrough, you may have encountered the problem where an MP will stop you on your way in to see Ambassador Kif Kroker, assert that nobody fucks with the NCR, and attack you. This despite being idolized (or whatever) with the NCR.

Turns out, this is part of an apparently unfinished little subplot where that MP would try to shake you down if you have a negative reputation on the strip, and the attack line wasn't properly restricted. I've just disabled that line entirely by adding a contradictory check (so that he has to both be outside the embassy and not outside the embassy for the line to fire).

Should solve the problem.