Why was Sunshine left off the crane diner?
 

I thought at first it was by choice, but by what she's saying on LF she was told by BB she couldn't go up?

she chose not to go up. bb asked one housemate to stay on the ground

Okay so... There's obviously a reason and she was seen on LF going into the DR not long ago.

Any idea what the 'twist/plan' is?

i think she got a picnic basket in the diary room.

sunshine looked so sad a minute ago all by herself.

i hope she gets a really nice treat loads better than the dinner in the sky thing

She suffers with vertigo and one HM had to stay on the ground and have a picnic instead of going up in the crane and to do a drawing task for the others, so she was the obvious choice to do it.

I feel sorry for her at the moment :(

Because no one likes her :)