Just wary of Shepper as can't see a way of reading what job entails beforehand unless starting the job and the clock ticking.
One today was visiting a shop, asking what the cheapest price of a product was. If the shop assistant said 2 brands that were given to me as buzz words then I would say congratulations you've passed the mystery shop survey and you've won a £10 voucher. They wanted me to get the sales assistant to write down their name and email address on a piece of paper which I had to photograph then leave the store so voucher could be emailed to them. If they didn't mention the 2 brands I had to say sorry you've not passed the test and not won a voucher but be prepared for next time.
So in my civvies, no letter of authority, asking a young female her name and email address....... Don't think so. Not even for the £3.50. This job was on behalf of a worldwide multi billion pound company.