There's something rotten in Alexandria. There is no way a community like that would have survived, let alone thrived, without Walkers or other survivors attacking it.
A couple things we know:
1.) Some group (the Wolves?) is going around and carving"W"s into people's foreheads. They are also dismembering bodies. Don't sound like a nice group of people.
2.) They have to be operating somewhere in the local area as there have been several signs of their handiwork both in Noah's family's community as well as just outside of Alexandria.
3.) Some group (the Wolves) broke into and destroyed Noah's family's community.
4.) This same group has not discovered or attacked Alexandria yet? I find this very hard to believe.
5.) Last week, Aiden said that they have cleared something like a 55 mile radius around Alexandria on their runs. This is another thing that is very hard to believe considering there are still Walkers all around the area and none of the Alexandrians strike me as self sufficient types that could clear that large of an area on their own.
6.) No one mans the look out tower. What??? That is completely crazy, unless there is a reason for it.
I think the reason is this. I wonder if the whole reason Rick's group was let into Alexandria was to help them defend themselves against another group of humans that is really in control of Alexandria. My thought is that another group of survivors (maybe the group that is carving "W"s into people's foreheads) is "protecting" Alexandria (maybe even helped build the walls) but at a high cost. That cost could be a share of the food, people to do hard labor, etc. The Alexandrians see Rick's group as a potential way to free themselves from their "masters" by having them fight them.
Deanna says that she is very good at reading people. This is one of the few statements of hers that I believe. She strikes me as the type that is not strong enough to pull the trigger of a gun, but smart enough to have someone else aim and shoot for her. I think that she is setting up a confrontation between Rick's group and the Wolves that will lead into the season finale. We know that the Wolves have to pop up sooner or later as there have just been too many references to them to NOT have them show up.
Sasha's reaction to the party was a little extreme in saying, "this isn't real", (definitley due to some PTSD) but I also think there is a good bit of truth to it. There is no way that group has survived this long without anyone else finding them and them having to defend themselves. No way.