There is no perfect solution to this problem. Everyone wants to sit next to their kids. No one wants to move to a worse seat. It's not like each flight has X number of families so airlines can't just block off the right number of seats. If airlines block too many seats, then higher fare last minute ticket customers are in middle seats because of so many blocked family seats, and they just get assigned to BE passengers. (I'd have to be on a very short connection to want a further forward middle seat than an aisle/window near the back) Families don't want to have to pay more money to sit with their kids, and airlines don't want to have to give up money because you're traveling with family. DL does make it WELL KNOWN the restrictions for basic economy when you purchase them from Delta.com. But often times even non BE tickets don't have seats together if you aren't booking pretty far out, and don't have any status.