You Will Not Return from a Trip to Mars the Same Person

By Astrum - which is mostly wrong. Here is the real story:

No one shows up at the gate to leave. Passage must, in part, be earned with colonists having to know how to use and fix some or all of the technologies that will be used in transit and the colony. Gravity will not be a problem. 

Unless centrifugal gravity works out, with multiple starships linked in the same way as envisioned in the 1000 Planets model, the trip would be a fool's errand.  There is no way to store enough food for the journey. It will have to be grown, as it will be on Mars itself.

Colonists will probably have to become SpaceX employees living in a colony model before liftoff (and without much in the way of pay) - and likely with some work in orbital colonies as well. Orbital colonies will be necessary to subsidize the Mars colony - as most colonists who would be worth having would not be able to simply pay cash and go. Cash explorers would go to Earth Orbit or the Moon - although because of the smell, I doubt the Moon would be much of a tourist destination - although I am sure Elon will take their money.