Well, that's something I could understand if this character was a noble, but adventurers haven't got anything to do with politics in their realms, they are just born there. I mean, it's something reasonable that you can't have information or the facilities of an allied country. People know for your accent that you are a foreigner from enemy lands and they wouldn't be willing to offer any service, but being imprisoned...
Anyway what really worries me is if the "nationality" of this character is enough reason for a Judge to execute him, or if that's something that only happens if the character is a rogue.