In most cases, a post which is "locked" cannot be modified in any way. Locking prevents...
...voting on the post (including close/reopen votes for questions)
...answering (for questions)
...flagging (though "in need of moderator intervention" flags are still allowed, except in the case of Historical Significance locks - see below)
Yet, it appears that several people were able to vote to delete, and able to delete this locked question.
Am I missing some loophole in the locking provisions?