I have to admit I am quite frustrated with the "domestic only" vouchers. I am living in Germany and almost all my UA travel is covered by intl. tickets. I guess I bought two pure domestic tickets in my "UA live" so far.
After experiencing broken legrests in C, defective Audio / Video, broken new-C seats on long distance flights as a 1K with intl. address in profile the vouchers are just not an option for me.
This leaves me with more and more miles - difficult to redeem thanks to Starnet!
On a recent IAD-FRA I asked the Purser to hand in the two cards offered for two issues (audio and video) to customer relations in FRA and request an international useable voucher - that is now three weeks ago. Nothing so far...