Actually I DID sit in the wrong seat in first class the other day. I was taking two flights that day and in the second flight I just went and sat in the seat I had sat in the first flight. I was a little shocked when someone came and asked me why I was sitting in his seat. I think I might have said in 2B and was supposed to sit in 1B, although I can't remember exactly, but the guy I think just thought I was dumb and sat in my seat. So it isn't always being strategic even if you fly a lot. You might just be too tired to pay that much attention.