Everyone finishes at the same time and there'll be 1-2 security guards stood at the end of a very long queue.
Everyone gets wanded or walked through an arch then bag searched.
Places like dixons/PCW repair warehouses etc do the same over here, but you're paid as you don't clock out until past that search point. I've even known it at places like clothes shops that suffered large "shrinkage". I know of a UK company who actually asked a large outlet to do this to their contractors.
This is what Apple meant by "for their benefit". They mean "well if we search you, we can't accuse you of theft".
Anyway, back to UK retail. I know of a large IT contractor who asked their clients to bag check the contractors staff.
Because each time they went to this chain to do a server upgrade or replacement, the staff of said store robbed their employers blind *EVERY* time a contractor of any sort walked in.
"Yeah, we had contractors again, that'll be where all those nice shirts went boss!"
The chain was asked by the IT firm to search the contractors on the way out and *NOT* tell staff below management level at the retail chain this was happening. I believe because it almost cost them the contract due to the theft accusations.
The duty manager was made to check engineers, the staff weren't told, all the stock still walked out the door anyway.
Surprisingly enough it wasn't the £250/day contractors stealing clothes and other random clart. It was the min wage employees of said chain. It almost cost a multi million pound contract. a 12 month job supporting 20-50 mobile engineers.
Anywho, random aside but I have seen this done for both staff targeting (dixons), and staff "protection" reasons (discount 'designer goods' chain). All paid for though.