Well, it's not really a long story, and the moral is - restricting zones saves lifes.
On my first fortress I've made a lot of small mistakes, one of them was digging stone outside the fort and then hauling it to a giant storage space inside. I also liked water pumps a little too much, creating fountains and small pools in every single meeting area I could. There was a channel in my main hall, for cleaning/drinking in case of alcohol shortage.
STONE STORAGE
/============== =============\
| |
E| |
N| VVVVVVVVVVVV| |VVVVVVVVVV |H
T| VVVVVVVVVVVV| |VVVVVVVVVV |O
R| VV VV S R
A -- TABLES -- P A O
N AND I N O
C -- STUFF -- T D M
E| VV VV A S
| VVVVVVVVVVVV| |VVVVVVVVVV |L
| VVVVVVVVVVVV| |VVVVVVVVVV |
| |
\=============== =============/
WORKSHOPS
VV is 7/7 channel. Note the fact I didn't remove ramps.
I've been producing wheelbarrows like crazy, because hauling stones from outside was taking ages. However, to my surprise, I never had enuff of them. So I made some more just to be sure it is not AI playing jokes on me.
After some time I noticed that I have far less stone in my stockpile that was mined out - and I don't think ONE mason workshop would manage to turn it all into furniture that fast. Huh, strange.
Then a cat went missing. His owner was a miner.
Then said miner went missing.
Then several other miners and haulers.
I was pretty sure I got a wampire in my fort when 3 dwarves were left alive. I was checking their stats to detect the vampire. Then... Eureka. I noticed none of them had hauling or mining enabled (two were crafters meant to mass-produce stuff, not waste time hauling, third was chief medical dwarf). In sudden realization, I checked inside the water channel...
There was a pile of wheelbarrows, corpes, wheelbarrows, stones, wheelbarrows and pets.
Haulers took normal path to the stockpile, not even getting close to the channel. However, everyone with wheelbarrow decided to take a shortcut, and because I was mass-producing them, I first ran out of dwarves rather than wheelbarrows. When the channel was still half-filled (it was filled by manually operated pump) they just panicked, dropping the stone and getting out of the channel. However, when it was 7/7, they started drowning, not noticing the fact they were already skilled in swimming and they were standing on a goddamn ramp.
My first ragequit.