Not both of them, no. Remember that CU*BASE doesn't consider a joint owner to be a member, regardless of what special rules your CU puts in place.  But in a nutshell, whomever can sign in to online banking can vote, but only once.  The system always looks at the primary member's SSN/TIN in cases where only one vote per SSN/TIN is allowed.  Joint owners whom you have included in the file must be entered manually via the CU*BASE voting feature, because if they log in to online banking they are voting as if they were the primary member on that account.