It's quite common for musicians who tour with an act's live band not to be credited as members.
Tennille Dragon, of The Captain and Tennille, played rhythm guitar for the band on one tour - and similarly, she is not credited.
So it is perfectly possible to tour with a band, and not be classed as a member, or appear in any interviews or publicity shots.
The most famous example is Darryl Jones who has toured with The Stones (Ronnie Wood plays bass in the studio) since Bill Wyman left, but is paid as a session musician, and not credited as a band member.