You seem to have missed the point - you don't know what he was going to do with them, or even if he was going to try to combine the t&e and plumbers tube, so how do you know if he was buying the right products? What some random guy buys in screwfix and in what combinations concerns you just as much as what I buy in asda - I wouldn't expect a chef to clock what I've got in my basket and start badmouthing me on a forum suggesting I was going to cook up some bogroll wrapped in bacon in a sauce made from milk and washing up liquid - they just happen to be things I need for various reasons.