That's like saying that if you get pulled over by a police, they will give you a driving test, even if you have a driver's license. You must trust the process. Your vetting happened when you applied for the visa. They might ask you a couple questions, but there is no requirement to produce the documents that you used to apply for the visa. If you are that worried, just be sure you can log into your bank account from your phone so you can show them your balance.