Arbiter in replica set connection string URI

[Allen]

Is it necessary to include a replica set's arbiter in its connection string URI? I'm guessing no, but I wanted to get a definitive answer. Thanks!

[Alistair Bush]

No, clients do not interact with arbiters at all.  

It is also not required to include all the primary/secondary servers in the connection string as the driver will query for this information.  Please note that it is best practice to have all primary/secondary servers in the connection string as it means the client will always be able to find a server to communicate with.

e.g.  If you had a replica set of 3 servers and your connection string only included 1.  If that server goes down then that client can't find the other replica set members.