Me and my sister/brother/husband/wife/whatever both play Power Pets from the same computer, but different accounts. How can I be sure that we don't get accused of multiple accounts?

First of all, make sure that there are no unbalanced swaps at all between the two (or three or whatever the number) of you. You can give gifts to each other and swap normally as long as all the rules are followed. As long as you follow the rules, you shouldn't have any problems.  more