Not only does she think quincy is fine so does the guard and some guy you meet who grew up there talk like it exists.
So either no one bothered to check on a huge town that they trade with or someone dropped the ball.
I think she says "near Quincy". I might be recalling incorrectly.
Piper says "Shh, Play along. What was that? You said you're a trader up from Quincy?"
https://www.youtube.com/watch?v=rcODRSEpYuU
I know of only one MM group that turned into out right Raiders. That is the group at Libertaria. The other Raider groups have always been there as far as I can tell. Some MM joined the Gunners, like the traitor that helped take Quincy in the first place. The rest either died or just faded into the wood work like Ronnie Shaw.
Reading the terminal at the Libertaria base and going from some things Preston says I figure the Quincy attack happened three to four months before you come on the scene as the Soul Survivor from Vault 111.
It is also entirely possible that the Gunners are still running trade caravans up to DC from Quincy. Selling off their loot from that area for things they don't have on hand. They don't always just attack every one and any one like the raiders do. Although they do tend to shoot first and converse later. Pay attention to the conversation between Macready and the two Gunners in the Third Rail to find this info.
The Quincy Massacre apparently happens in 2287 according to the http://fallout.wikia.com/wiki/Quincy_Massacre, the same year that the Sole Survivor wakes up. How long before the awakening isn't clear. Also, accordng to http://fallout.wikia.com/wiki/Preston_Garvey, the fight for Quincy wasn't over in a single battle; it wasn't until Clint left the Minutemen to join the Gunners that the massacre happened.
All this suggests a few possibilities:
1) Some folks may have escaped Quincy with their goods well before the massacre happened, and a few of them might have trickled into DC to sell their wares;
2) If people in DC only have second- and third-hand reports on the extent of the massacre, they won't have a solid reason to instantly disbelieve any claim of being from Quincy;
3) The Gunners themselves might be sending out or "conscripting" traders. They doubtless understand the value of regular supply lines while they consolidate and secure their position, and even Raiders seem to engage in trade now and again.
No idea if any of this has any relevance to Bethesda's intents wrt Piper's scam, of course. Just saying the idea of a Quincy trader might not seem impossible, or even unprecedented, to DCites(?).
Edit: Ninja'ed on point 3! Rrrghh...
When I was clearing out Quincy, I killed 2 caravan guards when I was looking for any gunners still alive in town.
ETA. The long's son was injured at Quincy. You get this information from reading the terminal in the store in Quincy. On another terminal it mentions Sturges and Moma Murphy and the traitor Clint.
More likely that she has incomplete and contradictory information about a huge event that neither she nor anyone except Preston (and gang) could have witnessed.
We are talking about a civilization that has neither phones nor cameras, after all. Or even decent typesetting, apparently.
Uhh quincy is actually a pre war city.... That settlement might be named it too but I think your nit picking up from quincy could be any number of settlements there....... The ghoul infested underground place with the dead settlers and dead cat comes to mind.
I think we are missing connecting to each other here......
I am saying Quincy (a real place err and according to wiki the 8 largest city in MASS) existed before the war, before the settlement quincy did.... And given that It is well a city, It is well likely to house more settlements than the ones the minute men lost.... (raider camp at at quarry came to mind after first type as well as a house of non ferals right next to the gunners that they havent gacked yet?... the underpass ghoul settlement i mentioned) New Quincy now under gunner control is what 3 blocks....
Quincy is a real place as is the quarry. The quarry is where alot of the dirt from the real Big Dig ended up as well as some bodies from the old southy days. It is also located right where they are on the FO map, though not to scale, its the same place. The gunners are morons and couldn't get out of a wet paper bag. They are listed as mercs but don't seem to take any contracts as they just attack anyone who seems to approach them, great business model. So they would have to get supplies or income from a steady supply to stay viable, caravans would seem to be their only option. Either that or news doesn't travel very fast around the commonwealth. Not sure I've ever seen the normal caravan people around DC.
Allright.... Uhh that dont seem to be working at all so.........
Why can the gunners not indeed trade (who now control quincy) sure stealing is always better.... But you sure end up with a lot of crap you did not want and not so much of what you did during a bushwack.
Maybe they trade for say ammo
Edit to be crystal clear from places they do not have the manpower to ROB, like diamond city.
is it just me or does the whole Quincy story feel very Alamo ish? not exact details, but I certainly get the same vibe.