Hi Boondock, That is an interesting thought and I doubt an abductor would want 2 girls at the same time. Listening to MB on that video she was expecting Lindsey back home that night. She said noting about the possibililty Kayla would be coming too, at least that I heard.
There is a RUMOR that the girls changed their mind on the way over to Kayla's house to both stay there for the night but who knows if that was true.
We have read somewhere she was only at Kayla's house for 10 to 15 min. That makes me think she wasn't necessarily seen on the way up to Kayla's house but on the way back which would mean it was a crime of opportunity. He saw her and decided this was the perfect time to make his move. IMO
I agree, it isn't likely an abductor would want two girls, but not out of the question. When I was younger a guy talked two girls and a boy into getting in his van. They were ages 11 - 13 and they knew the guy somehow. I'm not sure if he drugged them or what, but he took them out to the woods where he did unspeakable things and left them for dead. The boy made his way to the road and flagged down a car once the creep had left. The boy and one of the girls survived. And yes, this was in WA state.