Combat in systems with sight obscuration

[Q]

In systems with sight obscuration a combat will only occur if you have sensors to see the enemy and enter a sector. No combat will occur if the enemy enters the sector where you are present (unless he himself has sufficient sensors).
There are situations where this is o.K. but if you have defences on a warp point you would like to combat the entering enemy (as a surprise to him!). The only way you can do this is to attack when its your turn (if the enemy is still present and has not already warped) and then the enemy gets the first shot! Not very reasonable in my opinion.
On the other hand if I enter a sector where he is present the combat will always occur, even if he does not see me and I would like to sneak past him e.g. with a colony ship. In this situation my sensor ability becomes a disadvantage!