I can understand why an owner should have a choice to decide to get the BMS update or not, after all it is now their vehicle they have paid for it. Just because it is software it does not give a dealer the right to change settings on a vehicle if the customer expressly states it is not to be updated.
Although I do agree with your point of view that it still IS the owner property and he / she has the right to refuse the work, but I think we do have to consider the bigger picture a little bit here Dave.
The ZS EV comes with a 7 year warranty and as part of the conditions of upholding / maintaining that warranty, is that the owner submits the car for it's regular annual service intervals under the T&C's laid down.
Also, that any important safety service bulletins released by the manufacture, should also be applied at the time of that annual service.
This is one of the main reasons why manufactures strongly suggest using their dealer network, so manufactures software improvement gets applied at the point of service.
The warranty also includes the HV battery pack and therefore should be subject to similar T&C's.
Having worked in very large dealership myself many years ago, here is an hypothetical situation.
I relate this example to real attempted large warranty claims in my career.
E.G :- So, we have a four year old EV ( that is now more than half way through it's warranty period ) it has developed a major fault on the HV battery pack, it is determined that a large & substantial warranty claim is required to rectify the problem.
The very first place the manufacture will look, is the service history records of that car.
Trust me I know.
Service history is all in order - Great !.
Oh ....... But wait, they notice that the dealer has made a note on the system, that the owner has refused to allow them to apply the recommended update.
When this update was developed to help protect / improve the future life of the battery, but was not carried out earlier in the life of the car.
As a direct instruction from the owner of the car.
Well, I think we can quickly see where this is claim is heading !.
Refused on the grounds of none compliance under the T&C's of the warranty.
I have to say, this current non conformance situation has the potential of back firing in the faces of SOME of the dealers here in the future.
Why ? - SOME service departments are placing their heads firmly in the sand and avoiding carrying out the work, even though MG have documented evidence that they have received the service bulletin information.
If MG has gone to the trouble of issuing the service bulletin and is willing to pay for the labour costs, then surely THEY do consider the car needs them doing - plain and simple !.
Much cheaper than a possible future claim for a HV battery pack hey ?.
Dealers could circumnavigate this problem, by strongly suggesting / advising the customer that stress the importance of agreeing to the necessary updates.
But we know that many are not doing this.
It should be done correctly, by advising the customer of any important safety updates that the car requires.
If then customer / owner rejects the dealers advice, then it should be duly noted, then by doing so they will be forgoing / voiding any future claims under the T&C's of that warranty.
The current system is not robust in any way shape or form.
Let's hope this type of situation never arises of course.
But having personally seen warranty claims refused / rejected on a technical detail ( e.g. claim refused because the car was submitted for service outside of the 30 day time limit on service schedule ) it really is important to comply with the T&C's.
In main cases, it will largely depend on the size / cost of the warranty claim, just how far the service history of the car is studied.
With a claim on a HV pack, it's going to be both time consuming and very expensive in parts / labour and hire car costs.
But to keep this story balanced, I HAVE seen warranty claims accepted when cars are clearly just outside of warranty also.
These are settled on a "Sympathetic Claim or Gesture Of good Will" basis.
Again - A 100% solid dealer service history will be checked prior to granting the claim, you can be absolutely sure.
My son had a £3,000 "Sympathetic Claim" claim successfully paid out on a 3 year and 3 months old BMW with 25,000 miles on the clock.
It was a one owner car, service history was 100% bang on, the work was conducted at the same large BMW main dealers, each and every single time.
When agreeing the claim, BMW did so by pointing out that the service history had supported their decision in honouring the claim.
Food for thought at least.