Can't remember when you get access (especially as my settlement building is modded like mad), but you can go pretty far with them without having to actually do anything that betrays your personal morals too much. You do have to be careful, though... I helped the Railroad against them and, without saying too much in terms of spoilers, there came a mission that I think is necessary to complete to help set up the Railroad's plan to destroy them, and it sets you up as an enemy of the Brotherhood (everyone's fighting for the same prize object).
Actually, come to think of it... that probably explains why in that play-through I never saw, erm, a "certain thing" that showed up in others.
SPOILERS to explain below.
The mission in question is one where you go to get a nuclear reactor thingymabob from a building. Institute wants it to finish their self-sustaining reactor. Brotherhood wants it to power Liberty Prime. So I'm guessing that by going and getting it for the Institute, that prevented the Brotherhood finishing LP and setting it loose.
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Isn't that kind of like the real world, though? Like, depressingly realistic?
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I might regret asking this, but... What the heck is that game?!?
Also... "...hammering away..." Bow-chicka-bow-wow?
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At first, I found some interesting mods with that guy, but he got so full of himself and annoying (and his apparent attitude toward women makes me want to *****-slap him so hard) that I can't stand watching his videos or seeing these shirts.