Seat reservations are popular with train companies, but less so with passengers. Research by Transport Watch has revealed that many passengers do not sit in the seat that they reserved. A glance down any carriage will reveal that many of the reserved seats have not been claimed.
If one travels on a long journey, for example, from Cologne to Hamburg, it is like a game of musical chairs as passengers move from one place to another.
There are probably two main reasons why people swap seats. They may not like the look of their neighbouring passengers - a broadcaster on "Thought for the Day" once said that passengers always walked past his compartment if he was wearing his clergyman's collar!
And there is the design of the rolling stock. People prefer a seat with a view out of the train even if they spend most of the journey watching a film on their laptop computer, but in many types of rolling stock introduced since the 1970s, windows and seats are misaligned and the view out is obstructed. This problem has been aggravated by the prevalence of airline-style seating, which also gives rise to a luggage problem. On aircraft there there is secure storage for large items of luggage. On trains, people prefer to have their luggage nearby, and when seats are arranged in facing bays there is space between the seat backs. But when the seats are arranged airline style, the luggage space is lost and space has to be provided somewhere else, usually near the doorway where anyone can walk off with it.
One answer is to reserve a place on the train rather than a particular seat. Another is to provide seating plans so that passengers can choose where they sit, as in the example above from Sweden which can be downloaded from the train company's web site. The real solution, however, is to arrange the vehicle interiors much like the original Danish IC3 stock, which ensures that most people will be satisfied, wherever they sit.