I completely disagree with this.In such circumstances, I would hope that a TIR would be completed and an issuing error reported, however if no contract between the pasenger and the issuing TOC has been formed then there is no obligation to do this. This is a similar issue to any permitted groupsave discounted tickets which are not valid on Cross Country..
If I buy a York-Micklefield CDR, have I "formed a contract with XC"? The ticket is not valid on XC so no doubt you will say no.
If I buy a Micklefield-Leeds Season, have I "formed a contract with XC"? The ticket is not valid on XC so no doubt you will say no.
But the combination is valid on XC.
The "but you don't have a contract with XC" argument is completely null & void due to the existence of RSP, the TSA, the franchise commitments of XC, etc.
The argument you use could be used in the bus industry where there is no such framework, but it is a null & void & irrelevant argument in the rail industry.