Yep, like this person who used that method to steal £25,000 worth of goods from airlines: https://www.manchestereveningnews.co.uk/news/greater-manches...

Transport for London works similarly for contactless payment card acceptance on the tube, buses, etc. Cards are authorised in offline mode, with transactions processed overnight at the end of each day.

But they also maintain an internal blacklist of declined cards, so the most you'll get away with is one day's travel around London. Per card.

Oh wow, that's taking things to another level.