After Blind Betrayal, and if I have in as companin, BoS are hostile to me, and I can kill them over and over, but after I dismiss him we're all buddy buddy again?

(Not including killing named NPCs at Boston Aiport of course)

Yes. I shot down Vertibird on the daily while patrolling the area with Danse, then they never go hostile on me. I could do the same with the synth and no one at the Institute would care.

I took Danse with me when I went in to take down the institute, with the Minutemen.

from what I understand, you won't get permanent KOS status with the BOS until you either kill a named NPC, or side against them in a main story quest that sends you against them. just killing no-name NPCs doesn't bother them much.

Sweet. Thanks for the answers.

Gonna go mess up some BoS patrols, because I can.

I shot an unnamed legendary knight in the back of the head to get my first gatling laser- the two scribes walking with him on patrol never even broke stride, no consequences, no hostility, nothing.