Not customs, but I know how you feel about the lack of a way to do things without electrons! I was leaving a hotel early, had told them that, but when I went to check out (transport had arrived and was waiting) I was told the I could not check out, as they were doing the system close out for the last day. At first, I asked politely if he did not have a receipt book and a card "swiper." No....you have to wait....
Well, the next offer was "I understand that you have a problem with your systems, but it is not my problem. I am leaving now whether you are able to take my payment and check me out or not. What is it going to be?"
Amazingly, he figured out a way!
Doesn´t work so well with customs types......