As you'll notice from post 23 I quoted childwallblue's post which was number 21 and post 23 was the one you quoted. That was I referring to. Just because no one quoted your first post and three people obviously didn't read it before posting, doesn't mean I didn't read it and you need to keep drawing my attention to it.
Childwallblue also made the point about a ticket machine having issues for Northern staff, so part of the reason for my reply related to that specific point. If Northern are happy to install card only machines outside at unstaffed stations, why would installing one in an airport arrivals area with a security presence be an issue?