Thanks for the report but, as an observation, that's pretty standard throughout Europe. There are some exceptions but, generally, speaking, cross-border use is not normally an issue in Europe as long as you don't venture in a problematic area (eg: Ukraine, currently). OTOH, returning in a different country is much more problematic. Although they might operate under the same global franchise, car hire companies in each country are separate legal entities. You may well see it as hiring from Avis and returning to Avis but that is not how they will see it at their end. I suspect that it is true the world over. I have not checked but I suspect that hiring a car in Seattle and dropping it in Vancouver will be massively more expensive than hiring in Seattle and dropping off in Portland (assuming it is even possible, as, in some countries, cross-border oneways are simply not allowed).