The Feds do outlaw it across state and national borders.
18 USC 2421+ (MANN ACT):
Whoever knowingly transports any individual in interstate or foreign commerce, or in any Territory or Possession of the United States, with intent that such individual engage in prostitution, or in any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title or imprisoned not more than 10 years, or both.
Sec. 2422. Coercion and enticement
(a) Whoever knowingly persuades, induces, entices, or coerces any individual to travel in interstate or foreign commerce, or in any Territory or Possession of the United States, to engage in prostitution, or in any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title or imprisoned not more than 20 years, or both.
(b) Whoever, using the mail or any facility or means of interstate or foreign commerce, or within the special maritime and territorial jurisdiction of the United States knowingly persuades, induces, entices, or coerces any individual who has not attained the age of 18 years, to engage in prostitution or any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title and imprisoned not less than 10 years or for life.
2422 a) specifically seems to refer to persuading (et al) an individual to travel to perform such an activity. Or am I misreading?
2422 b) looks promising as it's pretty clearly saying you can't pimp someone out - but it only applies when the individual being induced/etc hasn't attained 18 years of age.
Can you knowingly persuade yourself? Yes you can. (e.g.,"I convinced myself of that fact.")
In one fell swoop, you are both persuader and persuadee. Victim and victimizer.
The law states "any person", which can refer back to the person of "Whoever". It does not state "another person", which would distinguish a separate person from the person of "Whoever".
True - but I was considering from the context of the original question, "One wonders...what is the legality of running a 'service provider' from the US but incorporated in Canada for something like this? Like, say, a scheduling/reservation app for this?"
Presumably in this context, our entrepreneurial poster is not looking to rent his or her own body out via app, but to assist others in scheduling of such assignations.
I'm pretty certain that anyone doing that would face some harsh legal opposition, to say it mildly. This falls in the "How could you possibly think this would be legal?" category, especially given how the guy who ran Silk Road got arrested. Even if it had been legal in other countries, we would still have arrested him and charged him.
18 USC 2421+ (MANN ACT): Whoever knowingly transports any individual in interstate or foreign commerce, or in any Territory or Possession of the United States, with intent that such individual engage in prostitution, or in any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title or imprisoned not more than 10 years, or both.
Sec. 2422. Coercion and enticement (a) Whoever knowingly persuades, induces, entices, or coerces any individual to travel in interstate or foreign commerce, or in any Territory or Possession of the United States, to engage in prostitution, or in any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title or imprisoned not more than 20 years, or both. (b) Whoever, using the mail or any facility or means of interstate or foreign commerce, or within the special maritime and territorial jurisdiction of the United States knowingly persuades, induces, entices, or coerces any individual who has not attained the age of 18 years, to engage in prostitution or any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title and imprisoned not less than 10 years or for life.