i sold some work last year, all the customers were told that he was helping me out, i felt that as i had had them a long time most didn't like change and once they got used to him, most were fine, he only lost a few which i replaced, also he payed half up front and the rest after 2 months.
i still speak with him and have passed some more work onto him that i didn't want, i suppose you have to trust your instinks, but then i'm totally honest and wouldn't con any one