Being from the UK we dont have the tipping culture of our American cousins. It is an alien concept to us and really rare that we tip anybody apart from giving cash to the cabin steward.
I have no qualms whatsoever in removing auto tipping and always have done on Princess and HAL, this is based on the opinion that having paid the company to provide a service, it is then up to the company to remunerate employees to provide said service to a satisfactory standard.
We use P&O a lot where its not an issue, and yes we are fully aware its in the price. We will not go with lines that do not allow us to remove tips.
And, lets face it, not all the 'gratuities' finds its way to the staff.