Also annoying in it's commonality is dwarf on edge of controlled area encountering a snatcher or goblin ambush team - and running *away* from the fort and gate.
Just had a dwarf retrieving something stupid and being followed by a dwarf child. They encounter a snatcher and run out into the open space rather than back towards the safety of the fort (with its traps, troops, and other reasons to head that way.)
They dodge the snatcher and it decides to run out of the fort - so all three of them are running on a parallel course to the west - while the guard squads are being sent out to deal with the issue.
And, of course, right outside the gate they run smack into a goblin ambush team (lasher and some crossbow goblins).
After a few misses the dwarven child gets hit by two bolts and is knocked down (and presumably out). At this point the child somehow *teleports* into the snatcher's bag about 8-10 tiles away right before the snatcher exits the map sending the triumphant message about the child being absconded with.
The hauler dwarf is a bit more lucky. He has militia reserve training, some light armor on, and also a shield and axe. He leads the ambush squad on a merry chase amidst the trees dodging bolts and parrying the lasher's attacks the few times the lasher catches up with him. By this time they are near the southwest outer area and meet a sword dwarf squad coming the other way. Hauler dwarf goes back inside while sword master chops lasher into about six pieces.
Snatchers and ambush teams are the main reason I draft, equip, and do basic training on almost all the fortress residents. Get their physical stats up so that they have a chance to outrun the goblins (and I have seen some do it) long enough for the regular military to get there. And with some armor and at least a shield they can hopefully block a few attacks (or arrows) and survive a bit longer. Also the benefit (and risk) of having a lot of crossbow armed dwarves about when something goes bad and suddenly an FB or some goblins on flying mounts turn up somewhere unexpected.