An update on how to avoid DCC for being Avis Preferred in Europe:

I was trying to sign myself up for Avis Preferred - since I live in Sweden I was redirected to Avis Europe.

It is very important that you DON'T use Visa or Master as your payment card because no matter what you do - it doesn't work on unchecking the option for not DCC.I first unchecked it and then press back button and that box was checked again!!!!!!!!!

Also once you have signed up you don't have any option to uncheck the box - even by going through update your credit card.

I don't have a DC or Amex so I wrote to Avis to ask them to permanently uncheck that box or sign me off from Preferred. I still haven't heard from them. I'll report back if I ever hear from them.