This was really useful, thanks FAQs.  I am wondering if I join a mining pool that automatically pays my shares through paypal would be a danger.  Could they send me whatever my proportions are and then later pull that back to their name?

What can I do to receive payment from pools like this, and then make sure I can not have the money taken later?

Is there a max time on how long someone can give money and then take it back, or can it be done any time?