Have you ever asked to be moved and for a valid reason and not to try and get an upgrade on the plane? I once sat next to a mother and her children and the children kept throwing food on me and climbing on me. I felt bad moving, but I needed peace and quiet and I couldn't get that. Another time I had someone very large sitting next to me I barely had any room and I was moved again, once the plane had taken off. I don't get offended if people move, because we would all like seats to ourselves, but some try it on to get an upgrade and I see the cabin crew telling them the cost. If you are polite and allow them to offer it, then it can happen rather than moan and complain.
I have only flown on a airplane twice in my life, the first time I sat with a friend and the second time I was too hung over to care - good thing both flights were only one hour long only! However, my friend was able to switch seats before when I was on a trip to Hawaii, and one of the flight attendant offered him a chance to sit in a open first-class seat. He immediately accepted the offer and did not regret do so, because his other classmates were cramped in their B-class seats and quite jealous of him. I'm hoping I get a chance like this in the near future.
I've never been asked to move, but I have moved for a couple that wanted to sit next to each other. The attendant then offered me a drink. I don't drink, but I asked him to give it to another woman next to me that was more than willing to get some free booze. For the most part, I'll buy a seat in the emergency row and they are reluctant to move people at random in and out of that row.
