Look, to me it's VERY cut and dry. You send a package to your lady friend. It's addressed in English, likely with a US stamp and US return address. That might as well have a "charge me more" sign on it. It's just the way it is in Thailand, especially the rural part - the postman sees that it's from a farang, and thinks "you can afford to give me a little something extra" and comes up with a "fee". You just need to let it slide and treat it as a cost of sending a package. It's no different than the special 200 baht fines on some highways if they catch a foreigner driving, or how ice to a foreigner's house somehow costs more than normal, or how government fees that are free need special fees paid if it's for a farang... the attitude is not malicious, it's actually quite socialist in a way - each pays based on his perceived ability to pay. That's why shopkeepers in tourist areas don't see it as ripping you off when they double the price based on you being white - they see it as being a fair price for someone of your means. Most people don't take it that way, but that's how they see it.