There are multiple places along the US Mexican border that are both easy to cross and don't have any sort of fence. Usually the large fence just stops. If you cross in those locations you are immediately asked to wait in line for a bus to be taken to a detention center where you are given an I-94 and an NGO funds your bus ride to New Jersey and New York where you will work under the table for cheap and skip your immigration court hearing. If you DON'T want to get caught, it is harder, since the border patrol knows where the crossing areas are and the terrain is more hostile although less patrolled.
Someone getting deported 6 times probably doesn't go through those easy points you mentioned. I imagine if youve been physically deported by the government, if they find you again at a point like that, you get sent back?
Yet if someone can come back in 6 times, I have to assume even the harder routes aren't THAT hard.