The majority of the members here are in the UK where we don't have to worry abou the police, because nobody's breaking the law
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Assuming you're in the US, how are you screening prospective clients? If you're not confident about somebody who's made contact with you it's fine to ask for references from other ladies they've seen (again, assuming you don't use any of the screening sites) but either way I wouldn't take somebody who wanted to book that far ahead seriously unless I'd seen them before.