We will have to wait and see. If they don't do anything or they say they did and the fault is still there then i'll have to push for ACC sensor replacement. If they refuse then i'll have to start talking car rejection.
Sorry to hear about your woes.
The fault can be fixed. Reject the car? That's a bit drastic, don't you think for a minor fixable fault? It's not as if the car is totally not drivable. Very much doubt VW will play ball.
You should have got a BMW!
We're well away from rejection, but if the car doesn't get fixed over a couple of visits I will mention it as a possibility to get them to take action.
Tomorrow, if they perform wheel alignment and find everything spot-on, then perform the ACC recalibration and don't have to deviate much for it to be seemingly perfect, and the system's sensitivity still seems off and the fault recurs then i'll be pushing for ACC system replacement. If all that happens and they refuse replacement, then i'll start talking rejection.
Just don't see why it should be so difficult for them to act upon the read-outs of the car's own sensors. If the sensor was giving a false fail signal then it needs replacing, but given the ACCs lack of sensitivity and for it to be willing to tailgate without caution, it seems to me that the system is defective (would explain the failure alert and the lack of sensitivity) or out of calibration (would likely only affect the sensitivity and not in itself cause a fault log).
If the ACC unit is as cheap as I read somewhere, and the calibration/wheel alignment dwarfs it's cost, it seems daft not to replace the unit and then calibrate/align. But then again VW and common sense do not always go hand in hand. When I got my MK5 GT Sport TDI170, it was in for frequent regenning and they replaced the cylinder head to no avail. A week later a software update cured the issue!