In fairness, the great frequency of trains on SR means that there is soon one behind, as my Gatwick example would have proved. The only problem is that, with all trains being very well filled, even outside the peaks*, the overcrowding issue becomes serious. GTR SR was telling people not to travel. That's OK for them, because, if I understand Bald_Rick correctly, they would have been compensated, but the pax would not have been, unless delay repay applied, and the taxpayer certainly would not be, as the loss of fares from the pax who didn't travel, and the cost of NR's compensation, fall on the taxpayer, a double whammy.
*Except perhaps the half empty GX services I observe when on that route!