Bletchleyite
Veteran Member
What happened is that, after selecting the ticket, I was warned that it was only available for holders of certain documentation and, importantly, it then asked me to enter the number on my documentation. I entered a random sequence of numbers and sale was refused. Now, whether that was because it had access to a database of all valid numbers or just that the format was wrong I do not know ....
Probably a checksum of some kind in the Railcard number (similar to the way credit card numbers work). It needn't be complicated, just needs to make sure that either (a) you have an actual Railcard, or (b) you have clearly deliberately made up a number cracking the checksum code and thus there is a record of obvious deliberate fraud.
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The fact is that in most instances all an automatic barrier gate actually protects in a practical sense is the minimum fare to the next stop along the line.
Indeed (and thanks for the link). What I was referring to was a key advantage barriers provide to passengers which is often ignored when people moan about them - they prevent accidental ticketless (but not Railcardless) travel.