EK are unlikely to reveal all the situations they would consider cheating - which is understandable, as that would give rise to other ideas.
Ultimately if you have different names, email addressi, PayPal addressi, delivery addressi etc. they are more likely to consider that several people share one common computer, such as might happen in an internet cafe or university or similar.
Different family members living in the same address might pose more of a problem - in a way I am lucky that my other half is not also a collector of Clacks.