The site cannot "accuse" someone of being two people but I take it you mean users affecting two (or more) different personae?
That should be spotted by the user's URL, unless he or she is careful to use different ones - and does not slip up and accidentally mix messages. If so then it should be easy to deal with but it need care if the messages are from genuinely different people sharing the sending instrument.
Other users might sometimes multiple identities by similarities of topics and style - including common spelling errors.
I'm talking about member A being falsely accused of being member B's sockpuppet when I know perfectly well that is not the case. This is something to which I am going to put a stop.