We have heard of many instances wher ebarrier staff, on SWT and elsewhere have displaced a lamentable lack of basic knowledge of the ticket and routeing system.
Either the TOC's are deliberately employing people who lack the intelligence to undertand even the most rudimentary points, or the training for such roles is hopelessly inadequate at many of the TOC's.
I must admit I think the lkatte ris more likely than the former. Given the cost and difficulty in dismising unsuitable staff once they have begun employment, it is a bit foolish to employ people without chekcing they have the skills and wit for the role in the first place.
It's easier to inform (staff and passengers) that off-peak tickets are only valid on trains arriving into London after 10:00 than it is to then explain the system of restrictions and the network area easement, also it means that more passengers end up buying anytime tickets when an off peak would have been valid making the TOC money.