The nomination for the best pick entirely depends on the quality of the post. Also, if anyone is creating great posts we should back them. Different curation team looks for different themes with specific tags. If a user selected twice or even more times, that simply means that the user creating some quality content. Note that this is a nomination, if the Steemit team finds any issue with the post quality they will question us for the nomination. However, when we curate we always try to reach many users who haven't been supported by any other team.