I’m inclined to agree. Anyone can pay for two accounts and only play one. That doesn’t make them a multiboxer. Multiboxing is actually an involved style of play with far more complicated key mappings, wow macros and experience learned. A higher challenge in other words. Sometimes you will see someone with another account on follow that could be the spouse of the person playing or a friend or someone they know just afk. That does happen.
I would chalk that scenario up to a bad group roll. Leave party and retry. Odds are pretty good you won’t get the same person.