I never used contactless until covid but of course now use it all the time. I 'hope for the best' on less than a fiver, eg a coffee but ask for a receipt for a basket of groceries. I've been offered the fond email receipt too. Always check bank statement, Paper A5 Diary says where I've been so likely coffee etc.

New topic but same headline I've heard of bank customers locked out of their account, presumably by robots and no explanation available from the bank itself, and no routine peyments made by the bank.