Beware - E-ticket for the NEC must be printed

We decided to call at the NEC on our way home from Spain this week. I ordered on line via the club. The e ticket option says you need to be able to print your ticket or display it on your phone but when I opened the pdf file after buying them term 3 very specifically said they must be printed. I checked with the ticketing company who confirmed they must be printed, otherwise entry is at the discretion of staff on the door. Glad I read the small print before we got there and persuaded a friendly campsite owner to print them.