Alright, actually this feature was already implemented right from start. However, it was overriden by some regression errors and a follow order ended up as an attack order.
This will be fixed by V1.06, which is - by this Saturday.
There're basically 2 types of follow:
1) Follow in the sector only, doesn't follow ship out of the sector lest it gets ambushed on the other side
2) Follow all the way, but you'll need to hold CTRL to trigger it.
But remember, if your ships can fire upon the enemy ship, it WILL do so unless the standing order - Silent Tail is set upon the ship designated to follow.
Silent Tail
If set to silent tail standing orders, your ship will always follow the targeted ship even if it's an enemy ship and will automatically follow it across sectors. As such you don't need to hold CTRL to trigger it.