The stake next to mine just modified the boundaries of two wards. I won't mention any names of said wards but I will say that this ward that gained these members is in a major city of about 100,000 or more. The ward in that city has seen many members become inactive and perhaps not pay tithing, so you know the drill, in order to increase members they are now changing their boundaries so a couple hundred members from the ward next to them join in. What do you think, its a trick if I have ever seen one, they are desperate for more members.

A lot of times, they will reassign ward boundaries to ensure they have enough priesthood for the wards to function. Or, like you said, if one ward has 800 members, 650 of whom are inactive, then they might re-do the boundaries to make things more even. That way, there is a more even ratio of actives to inactives.

My mom has lived in the same house in her small California town for 40 years and has been in all three wards in that town. Simply because people move in, move out, die, become inactive and they have to restructure the wards so there are enough active, priesthood holders and other members to make the wards run. The only ward my mom wasn't in was the Fourth Ward, which ended up being dissolved after a few years because the area can't support that many wards - it was created out of an optimism that was never validated by the numbers.

My parents live in one of the top 10 cities in the US and over the past 40 years have been in so many different wards and stakes that I forget how many it has been. At one time, their ward boundary ran along the strip of land electrical lines are on for 8 miles so a "new" ward would have enough active members.

They're just gerrymandering.