They have a habit recently of doing checks at Plumstead in the counter-peak direction (i.e. only checking tickets of people alighting in the morning or boarding in the evening). Whilst I can see the merit in that to avoid making people miss their work trains, it does appear a bit of a strange use of resources. I wonder whether they are actually there primarily to count people, in order to get better statistics for the next franchise? The official usage numbers are much lower than the true numbers.