Just a story to share, but hilarity ensued on AS458 last night SEA-LAX.
We were blessed with an aircraft swap from an -800 to -900, prompting a gate change from N2 to C20 and a mass exodus leading to a worse-than-normal gate licing situation.
I was in 6F with no cabin dividers. After the rush to board and the door closes, I noticed the FA in F, starting from the back of F, ask each F pax for their last name. I thought this was odd... until he reached the first row.
(At this point I remembered that F was booked 12/16 with 2 upgrades cleared, per gate monitors. And here at this point there was only 1 empty F seat).
Couldn't hear the woman's side of the convo, so all I have is the FA's monologue, since he was facing us:
"I'm sorry, I'm going to have to ask you to move..."
"This seat is reserved for first class passengers..."
"You tried..."
"Yes, I understand..."
"It sounds like the gate agent did everything she could..."
"You tried your best..."
"I'm sorry, I can't do anything..."
"I'm really sorry, there's nothing I can do..."
"I know the seat is empty, but I still have to ask you to take your seat..."
"I'm sorry, I'm not allowed to take bribes..."
It keeps going, pretty much to the point where this woman has lost all sense of dignity and shame, practically begging to stay (and yes, I did have a flashback to the Seinfeld episode where Elaine tried to sneak into F

)
Finally, probably after delaying the safety announcements for another 5 minutes, she gets up to make the walk of shame back, still protesting her move to the FA escorting her back.
(Did I mention... no dividers to block ANYONE's view?)
When she reaches my row, she stops and claims she doesn't know where her seat it, all the while eyeballing 6C (oh, hell no! - says my brain). The couple in 5AB looked at her wide-eyed as well, since the man in 5B was actually in 5C and moved over because boarding was done. She feigned fumbling for her BP and blurting out, "I think I'm in C-something..." to which the FA replied, "You're in 14C, ma'am." Pretty much everyone in Rows 2-13 rubbernecked watching her make her way back.
And as icing on the cake, a 2nd FA had to bring her shopping bag (which was the size of a rollaboard) full of junk back to her (flashback to when I noticed that some F pax was protesting her having to put said bag back in the overhead bin because she was "in the bulkhead.")
See? Not having a cabin divider can be loads of fun!