Ah, the first hitch in the Bit. They can't really drag others in without implicating them in the Bit, and not everyone's going to be okay with pranking a newbie. And in any case, two people is a Bit, more than two people is a conspiracy. How to answer...

"I don't know how common it is, but I think it happens sometimes. One of the passengers before us showed up with her brothers."

Which is the truth, while also preserving the Bit.