Hi. It's not a common practice. Situations like this are exceptions. I close aditional accounts when I found them or when they are reported and it is obvious that is the same person.
There are a few cases that I know of members from the same family using this clubs. It is possible.
But I can't know if each situation is real.
In your case, those two members said that they are different persons, members of the same family.
If a person is using two accounts, it means that it will have a double sending limit then the rest of the members. It would not be fair for the rest of the members that have similar accounts.
Even in this situations, that person would recive back letters proportional with the number of sent letters.
If you send two letters to the same person, you would receive back two letters. You don't have to feel cheated.
Situations like this should be avoided, because just like in this case, it creates confusion and suspicions. If two different persons from the same family are using this clubs, they should make it very clear that they are different persons and not let room for confusion.
There have been other questions about those two accounts and others have canceled without asking. In the end, it's not a real advantage for someone to use two accounts. It might be a drawback.
