You hit my pet peeve with this common mispelling: it's shoo in (like shoo fly pie). Meaning you just need to wave your hand and say 'shoo' to get somebody in (and not that you have to kick them with you shoe).
This:
The conventional spelling of the noun meaning a sure winner is shoo-in, not shoe-in. The term uses the verb shoo, which means to urge something in a desired direction, usually by waving one’s arms. The idea behind the word is that the person being shooed—for example, into the winner’s circle, into a job, or into a field of award nominees—is such a lock that we can shoo him or her in without hesitation.