GOOD NEWS !
It is no problem to add the hacking function to the movements ETA 2801.
We have tested and we can do
So - no worry about a special limited watch.
Now it is perfect in any way .-)
Please see attached pictures:
1 - One picture is with a moving balance - you see the small part in a distance to the balance.
2 - The other picture shows the part how it stops the balance !