I don't really ever do it. These days my wife and I have a 9 pack, which make up the majority of the games we go to. We have pretty good seats in section 215, so no real reason to move up. The only exception would be moving up a few rows in the same section I'm, if say by the third or fourth inning no one has showed up to sit there. With how crowded Miller Park usually is these days, I don't think there's any real justification for buying a terrace reserved ticket and then moving down to the loge or 100 level. I guess if the usher says it's ok, that's one thing though. I just can't stand when you're watching the game, and the real ticket owners show up to get the seats in front of you, and then the squatter occupants take five minutes to leave. Just bugs me.