I used the TPE website yesterday to purchase several APs (TPE between Manchester and Liverpool/Middlesbrough if it makes any difference). After the fourth booking, the following message appeared:

Does anybody know why? My first thought was that it was an anti-fraud measure, but if so it's rather redundant as one could simply purchase 4+ journeys in one booking.
I've spoken 3 times with TPE (web sales/web support/general customer relations) over the last 16 hours, who despite having the best intentions, were unable to explain it.
Thanks in advance for any insight.
TPE said:You have now made the maximum allowed number of purchases today (4). You will not be able to purchase any more tickets today.

Does anybody know why? My first thought was that it was an anti-fraud measure, but if so it's rather redundant as one could simply purchase 4+ journeys in one booking.
I've spoken 3 times with TPE (web sales/web support/general customer relations) over the last 16 hours, who despite having the best intentions, were unable to explain it.
Thanks in advance for any insight.