What stops abuse of Any Time return tickets?

[WhatYouNeed]

I recently travelled using an any time return that lasted one month (using a phone ticket with the Trainline) When I got on the barriers were open so I didn't scan the ticket, and when I got off there were no barriers at all. On the train the inspector did scan my tickets QR code and I assumed this would deactivate it.

However, a few days later it's still appears active on my phone. I have no intention of doing so (I won't be making the same journey again any time soon) but what would stop someone reusing this ticket?

Obviously every ticket system is open to abuse but this seems like such an easy thing for people to do that I wonder why there aren't measures in place to prevent it.

 

[Wallsendmag]

The scan details are written to a TOC specific database which can and mostly is shared with other TOCs. The next time the ticket is scanned you have he option to see previous scans.