I've played a few games and but have never used any of the stealth units.  I read that the stealth mechanic was broken at the start of the game (AI would see the units on the world map).  However I believe that's been fixed now 

Are the stealth units worth using?

Cam the enter into other cultures without causing a declaration of war?

peter79 wrote:

I've played a few games and but have never used any of the stealth units.  I read that the stealth mechanic was broken at the start of the game (AI would see the units on the world map).  However I believe that's been fixed now 

Are the stealth units worth using?

Cam the enter into other cultures without causing a declaration of war?

No, to the second (and because of that No to the first).  That is the one change that would make them worthwhile 

Also if they were available earlier... say Scouts don't upgrade into Horsemen, but into Classical Era "Spies"...like Scouts but with Stealth that actually works (letting you move through enemy territory)... then let Medieval Sabotuers expend themselves to Ransack a district immediately (if not detected)

[Those also would be some ideal units for Rebellions]

Stealth unit can enter other players borders even if they don't have open borders, but only as long as the stealth unit stay out of sight.

Krikkitone wrote:
That's not my experience with the Saboteurs (sitting in enemy territory after a war they couldn't move around in there only move out)  [maybe that was prepatch or its bugged.  (Possibly the detected/Stealth status should be better indicated)

Not tested after war.

i tried them not too long ago and yes you can enter into their territories scout around however when they get spotted by enemy units and felt like the ai knows where i am then you trigger a trespassing grievance and forced to leave with the unit or it was attacked on sight (depends whether you have non agression i guess)

i checked i couldnt ransack that would have required war, however you can zoc from 2 elevation upper if you are lucky thats next to a road :)

I did a test vs AI again, putting my Saboteur 4 tiles away of any their district. I believe they noticed it immediately. This doesn't always happen though, may be AI not always sends someone to intercept, but in my case it sent someone every time I tried to put my Saboteur at distance of 4.

It's been hit or miss for me, possibly as patches roll out?  Two nights ago I was able to waltz some Partisans into a neighbour's territory without Open Borders or War, and the "Move" command helpfully kept me from moving too close to the foreign districts without declaring war.  I messed up by commanding the Partisan to go through some fog of war, and near an elevated district I wasn't ware of. That empire hit me up with a very expensive trespassing grievance, so it looks on the face of it that stealth was working as expected in that instance?