Great Western Coffee Shop

I had a strange experience at Crawley Station today. I meant to put the return portion of my ticket to Bookham in the ticket barrier but without thinking I put my usual season ticket (which is for Bookham to London zones 1-6) in instead. The ticket went through and to my surprise when I picked it up, the barrier opened. Why? That ticket is not valid for that journey?

Perhaps just another of the vagaries of the ticketing system, Surrey 455  ::)

I can't say specifically, but having done it myself long ago, creating the ticket checking data was often a highly-manual process involving maps, highlighter pens, a darkened room and a bucket of cold water to plunge your head in when it all got too much. The starting point for setting up gates at a station for the first time was often taking the data from a vaguely-similar station (maybe one nearby, maybe just a similar distance from London) and modifying it. Quite easy to leave a stray bit of spurious data in, and quite hard to spot; funnily enough, people tended to complain more about tickets not working that should do than the other way round!