Listing "memberships" on academic CV
The general rule is "if you don't want someone to ask you about it, don't put in on your CV." Including such memberships is still standard practice for many as they signify both your involvement and willingness to continue to participate in your field. So, don't think of these memberships as padding, think of them as opportunities to highlight your accomplishments - unless you really can't find a positive way to discuss these memberships, in which case they should not be included.