R2, I know that "vacay" is short-hand for "vacation." Wouldn't it be "whom" and not "who?"
the lead from Hawaii 5-0
Michelle Williams drove Heath all the way to Pennsylvania for one but at the last minute he wouldn't go in
Mr. Zeta-Jones, Michael Douglas
It would be easier to list who hasn't.
No, R6. There's a semi-lucid explanation of the who/whom rule at the link -- or you can just trust me that "the celebs who went to rehab" is correct.
But "vacay" is never acceptable, if only because it sounds stupid . So does "celebs", for that matter, though it doesn't bother me as much -- & "rehab" actually sounds OK for some reason.