Once the 'bad' site captures your ranking from G, is there any need for them to continue 302ing your page? Seems to me once they knock the good site off and become acknowledged as the 'official' version, they can change the content to be anything they want. Is that correct? Then, if you've been 302'd long enough ago, it would be impossible to detect? or is it necessary for them to maintain a detectable index entry indefinitely?