"Very legally" if you ignore the fact their golden rules disallow having more than one account. Now, if you meant that in the sense of two different people acting in collusion and gaming the system to buffer each other, then indeed it's a technically "legal" tactic their staff don't seem to think needs any addressing.
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For maximum effectiveness, make sure to use the IP filtering feature in both clients to block the entire IPv4 address space with the exception of each other and RED's tracker... if you were so inclined.