Interesting... This happened to me on several kont flights. Despite my questions at the gate, none of the (mostly clueless) handling agents could provide me with a reason. The person/people in my original seat were not with babies or special needs in any way. I know for a fact that many airlines have a rule that seat changes without pax knowledge after the boarding pass has been issued (whether OL or in the terminal) is only done for strictly operational reasons (for example, the original seat is broken, unexpected UM has to go in a certain seat, etc.) So why does LH feel free to just change C class SEN on the day with no explanation?