User blog comment:817603/Lucy Requip/@comment-24264679-20151226203003

Doesn't happen as often as people think and that has already been solved by the spirits passing through the gates themselves. Which by all means is better. Also Lucy has telepathy among her and her spirits so if someone steals her keys she could just tell the spirits to open their gate.

If the Spirit is in enemies hands then it makes it easier for the spirit to attack.