using a proxy/vpn and buying yourself gift cards from another account should give you reasonable protection, yes. As long as you have enough gift card balance, Amazon won't ask you to add a Credit Card. But it's cumbersome, etc.
Amazon recently started blocking my Kindle purchases basing on the fact my IP locates me in Japan while my primary address is set to the USA. When I switched to the gift option (using the same account) it worked without any problem even though I was still using the same Polish credit card.