I forgot to post this yesterday, after I wrote it: (And only to be fair to Smith...apparently, they didn't actually ask him to leave.)
There are several articles now saying that they didn't ask him to leave, therefore he didn't refuse. The most coherent explanation of that is this from the Huffington Post:
'But according to unnamed sources who spoke to
TMZ and
Variety in reports published Thursday, Smith, a lead actor nominee, was never actually asked to leave. According to the reports, there was division among academy officials on whether to remove Smith, and the mixed messages never led to a consensus.
A
Monday CNN report also squared with that version of events.
“Academy leadership strongly considered removing Will Smith from last night’s broadcast following the incident,” a source told
CNN. “There were immediate discussions but the Academy decision makers were seated in various spots in the Dolby Theater and couldn’t mobilize to make a decision before he won best actor.”'
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What I find plausible is that they were seated in various spots around the theatre, and that by the time he was awarded Best Actor, which came shortly after, they hadn't had time to discuss it...it's pretty unprecedented, so they would have to have decided what to do. Hollywood Reporter says that the show's producer spoke to Smith, but that he told him to stay.