Well maybe your example gets into murkier waters, but AFAIK, the ticket itself was a properly issued one created by the train company, it just wasn't valid on the bus, in the same way as any other random bit paper wouldn't be.If a counterfeit/fraudulent copy of a ticket is NOT actually a ticket, then are you saying that an Inspector would not be permitted to withdraw it, because it belongs to the customer, and the bus/train company etc has nothing to do with it's issue/creation?
I assume that drivers don't look at tickets on boarding any more?