Imagine this. You're an MP trying to persuade a rail company to change its mind over the closure of a station ticket booth. The rail company has a Freepost address for customer complaints and invites people to write to them. So you hand out postcards to commuters urging them to do just that. You are then told by the rail company that they will bill you for the cost of the postage. Do you...
A) pay up and vow not to do it again
B) tell them what they can do with their invoice
This happened to Labour MP Joan Ryan. The Rail company was First Capital. She chose option B.
If Ms Ryan would like to get in touch, I'd happily share the Freepost address with my 70,000 readers. That should teach them not to be so crass.