I was playing through the "Classic Inspiration" quest given by Michael Angelo on the Strip, I photographed the sites Mike wanted me to, then I went to his workshop and before reaching him and getting my reward, an NCR Trooper 'MP' ran to me and said something like "Finally find you in the strip, nobody [censored]s with the NCR" and started shooting me, before i could do something, Boone blows his head off and I gain NCR Infamy to "Smiling Troublemaker".

Is there an explanation for this? Is this for the "Don't trend on the bear" quest? What do I do

lol there can be so many reasons why they attacked me, My guess is that you helped house a bit too much.

I helped him, but after I got the "Don't trend on the bear" quest, I stopped doing so, I even killed him, does it means the same if I helped any others on the Strip? Wierd :S.

Also, with the Smiling Troublemaker reputation, will I be able to continue on NCR's storyline?

I just got this quest when I finished Part 3 of The House Always wins, my guess is that an MP will soon come and shoot me, will report if it happens.

If you are willing to see, try saving and doing the Angelos quest after having the Bear quest, Angelos on the back of the Strip next to the Embassy.

Quick Update: I catched a save before the trooper ran into me, I didn't walk straight to Michael and went out, another MP Trooper ran into me saying that if I paid 200 caps, they would calm down, I asked why and he said I was doing some strange things around they didn't like, most likely helping with the Strip.

Well, anyways, thanks for the help.