In London you generally don't even get a bus, rail or underground ticket. You just swipe the contactless pads to hop on, or in and out at stations. Very occasionally an inspector just holds a hand terminal to your card to check you paid.
For a ticket inspector, there is hardly any information to discern if a journey has been made when using a Contactless card. Furthermore, anybody who uses this method knows that it can be several days before a journey shows up on the list of transactions. Although, it is largely to do with how the TfL payment system was implemented, with Contactless being more of a hindsight. However, it is significantly better than nothing at all.