Whilst talking about blocked seats, I have long wondered what check-in agents see. On one recent trip I asked the agent to move me because someone had sat next to me (outrageous, and me a Gold !), and he moved me and then said - "Oh someone has just taken the seat next to you again", which turned out to be a blocked seat. Can the check-in agents see a difference between occupied and blocked, and does the system start releasing blocked seats if they are needed or can the agent override that and allocate them (.e.g. if someone preferred a different seat to that they are in) ?