Your Dr seems to have been negligent so because of that you advise everybody that they should not get a lapband.
People get organ transplants and their bodies reject them - would you advise them not to get the transplant?
Women get pregnant and die in childbirth - does that mean people should stop getting pregnant?
You can get MRSA in hospital - does that mean noone should go into hospital.
You can have surgery for something minor and end up dead because of a blood clot or some other unforeseen complication.
You can take medication and have a serious allergic or anaphylactic reaction - should everyone give up taking medicine.
Yes you have had a bad experience and I am sorry about that. It sounds as though the NHS or whoever it is in Scotland messed up. That is hardly a good reason to advise others not to go ahead. If you want to caution others maybe you should make them aware of the risks of this particular Dr or the NHS in general.
Life itself is risky. There are no guarantees. Imagine trying to live your life without taking any risks - that life would be no life at all. You wouldn't be able to go outside your front door because you could get struck by lightning or run over by a bus. You certainly couldn't go in a car as that is one of the most dangerous things people do every day. But staying at home is dangerous too, that is where most accidents happen. You could:-
Have a fall
Burn yourself
Get electrocuted
Be poisoned by food, or chemicals or gas or plants
You certainly wouldn't want to have sex as that could involve catching a life threatening STI
You would probably be so bored sitting in your room wrapped in cotton wool to protect you and keep you warm that you would over indulge in food and then you would get fatter and fatter and fatter and probably die prematurely anyway from a stroke or heartattack