What exactly do you mean by this?
Where there is irrefutable proof that a TOC, or their agents has failed to make the necessary checks to confirm that the ticketless traveller's version of events is correct.
For example;
If the ticket office was closed when NRE suggests it should be open, there will be a staff logged entry confirming that fact. the TOC or their agents can check that
If the TVM is working normally at the material time, it is relatively simple to get a print-out showing the issues in the time period - if a traveller who is reported by an RPI claims it was out of order, that should be checked
If the route is one worked by conductor guards (as all are in Wales) a query should be made with the conductor to see why no onboard revenue check was made
If you, I or A.N.Other have
proof that none of these checks have been made when allegations are laid by a company, then it is fair to say that the TOC or their agents have been negligent and should be challenged, but if not, it needs more than a vague suggestion that they 'don't check or don't follow procedure'.
Given the high number of successful prosecutions for fare evasion in Wales over recent years, it appears that checks are made.