Hidden-city ticketing with Lufthansa Express Rail

Question

I am about to buy a ticket from an Italian city to Frankfurt, and I just noticed that the ticket is much cheaper if I select Stuttgart as final destination.

The flight to Frankfurt is direct, whereas the flight to Stuttgart is via Frankfurt, the first leg on the same flight, and the second leg an a DB train carrying a proper LH flight code. I believe this is part of the Lufthansa Rail&Fly program, but I am not 100% sure. This should be part of Lufthansa Express Rail, as pointed in an answer below.

My question is the following: can I buy the second ticket for cheaper, and simply stop in Frankfurt? Will Lufthansa notice?

I will be checking a bag (which usually makes hidden city ticketing impossible), but for Rail&Fly Lufthansa clearly specifies that the checked bags are not transferred to the train, it's the passenger's responsibility to do so.

Answer 1

One thing to note is, that this is not Rail&Fly, but rather it's named Express Rail.

The difference is, that with Rail&Fly you get a flexible train ticket to and from the airport, which is valid one day before departure as well as one day after arrival of your flight. Because of this flexibility, you are responsible to make it to the airport in time, i.e. you need to make sure, that you choose a connection which arrives early enough at the airport.

On the other hand, with Express Rail (which you have booked), you book a specific train under a Lufthansa flight number. In this case, it's the same as you would have booked a connecting flight, which also means, that in case of train delay, Lufthansa will rebook you onto the next available flight (in your case it doesn't matter, since the train segment is after the flight segment, but it's important in the reverse case). In those trains, at least in the past, they have specific Lufthansa employees, which also have checked that passengers booked for that specific segment were on the train (i read those reports on FlyerTalk). If you have a return flight afterwards, you might get problems, if they check specifically on your train and if they actually sync back those information to the Lufthansa booking centers.
If you don't have a return flight, then you will have no problems by leaving and not getting on the train in Frankfurt. For me personally, that would be the deciding factor. If i wouldn't have a return flight, i would book the hidden city, if i would have, i would book it only to Frankfurt.