To be fair he was fully aware that the shop operated under conditions and terms different to a normal high street shop and by taking advantage of the preferential terms inferred his agreement.
At no time did he check the T&Cs or ask a member of staff if there was any conditions before he took advantage of what he clearly knew to be conditions that varied from the average high street retailer.
He knew he could only be there as a guest of a member. He knew that gave him advantages not available to the general public (i.e. preferential pricing). He knew he was subject to the terms and conditions that governed membership as he explicitly asked if it was possible for him to pay separately (a given in any other situation). He knew he could not purchase the items there without using the membership of his friend which he knew carried terms and conditions with it.
He was not personally searched at any time, the goods on the trolley were reconciled against a list of purchased goods before departure.
He had already consented to the goods being checked and listed once (at the till) and had never suggested he would object to that act being carried out twice.
When offered, along with every other customer, the check of goods at the exit (to perhaps be helpful and make sure nothing had fallen off the trolley and gone missing on the way out, who can say
) he did not take the opportunity to decline, to ask for managerial intervention or in fact just declare he was unprepared to have the goods checked again and return them for a refund.
The only thing i'm not sure of of is if the OP is trolling or just not odd.