To all the battlefield upgraders, yes, it is an inconvenience for me to change my seat. Just by asking, you put me in an awkward spot. Do I stay in the seat that I chose and wanted while being a jerk, or do I inconvenience myself and sacrifice my choice just so you can sit next to Schmoopy?
It's one thing to change seats on a long-haul flight, that I get. But to ask on a hour long flight, really? More often than not, people will know you're together. If they want to switch seats, they will offer -- I've done this and i've seen others do this. But to ask, puts the person in the seat in an awkward position and it's rather selfish of you. If it's so important you sit together, then you should get seated together and that may mean sitting in the back or buying a first class ticket.