The point of the question is to discuss whether seat reservations on trains (for individual seats) should be abolished.I don't entirely get the point of this question. People, not just families or large groups want to sit together. The fact that people were even charged to reserve seats is ridiculous. If you're trying to make the trains a more customer-hostile environment then banning reservations or applying a surcharge to them is they way to go about it.
What other people are there that would want to travel together that aren't part of a group, or friends?
Some trains are already hostile because of the reservation problem (see below).
The problem is the move in expectation.Seats that are reserved but not occupied are free for anyone to use - if you don't wish to sit there, then don't.
If someone regularly gets on a train that has reserved seats but nobody sitting in that seat, they may regularly sit in that seat. As time goes on, the person may think it's their right to sit in a seat and cause some sort of awkward conversation if someone does turn up to sit in it.
What happens if someone doesn't feel they can challenge the person sitting in "their" seat? So they take another one, then get told off by the owner of that seat.
It's a mess.
I've witnessed people reserve seats, then tell the ticket seller they don't plan on using that train anyway. What a waste of time for the ticket seller, and everyone else in the queue having to wait.