Scott Walker Tweet Pre-empts Formal Presidential Announcement

Scott Walker, the governor of Wisconsin who is expected to formally announce his campaign for president on Monday, on Friday apparently pre-empted his announcement on Twitter.
“Scott is in,” read a tweet posted to Walker’s official feed late on Friday afternoon, accompanied with a black and white picture of the governor waving from a stage. “Are you? Join our team today.”
The tweet subsequently ceased to be visible on Walker’s timeline, though it could still be seen online, prompting some observers to suggest its posting could have been a mistake.