It is a common story for an officiant to learn her couple has been together for a year or two or three. It is equally common to hear a line similar to this one: “we’ve been together for many years, and we finally decided to get married.” I’ve even married a few couples who had teen-aged children together but never picked up a license and exchanged vows.
Likewise, this couple already joined their lives more than a few years ago. Therefore, for them, an elopement away from stress and formalities made perfect sense.