Power imbalance

One of the arguments for statutory rape laws is that there's a power imbalance between an underage minor and an adult. In a scenario where a 13-year-old is approaching an adult online, volunteering his address, and inviting the guy to travel across the U.S. to have sex with him, is there a power imbalance? What is preventing the teen from fending the predator off by saying, "No thanks" and blocking him, as opposed to saying "Here's where I live; don't forget to bring the condoms, and remember, I like strawberry peach-flavored wine coolers"? To me, that sounds like it's the teen who's really calling the shots and getting the adult to do what he wants.
The son of a friend of my mine used to brag to his mom about how he could easily find gay men who would pay him several hundred dollars a night for sex. In that way, he was able to afford a lifestyle where he wasn't financially dependent on his mom, and she couldn't tell him any longer, "As long as you're under my roof, you obey my rules." (His mom was a lesbian who had him by some random guy she got to fuck her so she could have a kid, which adds further support for my argument that dads are NOT as dispensable as feminists would have people believe.)
At what point do we have to conclude that it's really the teens who are in the driver's seat, and behaving in a way that borders on exploitation of horny adults who have no choice but to obey their instructions and pay exorbitant prices if they want to fulfill their fantasies?
People often say it's adults who are able to prey on teens' desire for affection, approval, etc. How is that a stronger drive, that renders people more susceptible to manipulation, than adults' sexual urges? It's one thing to bring up teens' physical dependence on adults for the necessities of life, but once we get into the territory of factors that make people susceptible to psychological coercion, it gets really iffy because some adults have as little self-control as teenagers.