This sort of used to be the case with Heathrow Express in London. There was a lot of signage that suggested to the unwary that Heathrow Express was the "right" way to get into London. Now, especially with the Elizabeth Line, while you can save a few minutes with Heathrow Express, that's really not a cost-effective alternative for a lot of people. (And Piccadilly may be a better option depending on your luggage and where you are staying.)