A real world couple only as a huge exception. Friends? Definitely not.
One exception that comes to mind is Izabel, since Don Roberts does not like to post himself, and they both work on their stuff together. It´s 99% Izabel posts anyway.
Another example I can think of was when a non-native speaker had a friend help him create a post. The friend is a member on the RPF himself, and he announced in the post that he was making a post for the friend with the friend´s account.
Everything else is way too confusing and does not guarantee the safety of members when it e.g. comes to transactions.
It´s mandatory that people do not share login-information with third parties, by the way.
When nonsense posts are made that are in violation of the RPF member guidelines, the account holder will be held accountable ( :lol ) for the violations .
If you notice that an account is used by two or even more people, then please report it so we can have a look at it.