What do you mean, "not noticing"? She kept a hawk eye on it, to make sure he didn't cheat her on her cut of the trade.
Typically younger teens are used for the exposed part of the work because they can only be sent to juvie, at most; and the records are sealed or expunged at majority, giving them a clean felony slate to start with on their march toward an adult '3 strikes'.
I was giving her the benefit of the doubt. Although, your assertion is very plausible too.