General Discussion

Customs officers are authorized to operate within 100 feet of the Port of Entry after that they cannot legally continue, even a hot pursuit. For this reason Border Patrol officers are also stationed at Ports of Entry.

Border Patrol is authorized to interdict in the areas next to the border.

ICE is authorized to investigate and arrest through out the United States and its territories.

The Supreme Court has defined an area next to the border where the Border Patrol is authorized to act, the reason for the size of the area I believe is because of the rugged geopgraphy of the area.

During the Obama administration the Border Patrol has been ordered out of many urban areas (like Las Cruzes, New Mexico) as part of their regular patrols and those areas are supervised by ICE who is operating under strict guidelines to focus all resources on illegal aliens who are involved in criminal enterprizes and leave the others alone.

You began by objecting to the particular way your friend was treated and it is possible there was an error by the agents in not conducting the secondary visual inspection there, and I made a constructive suggestion.

The facts are that the highway checkpoints are continued because once the drug and human smugglers jump the fence the most effective way to get them is when they try to leave the area. Beacuse of the desert and mountains of the Southern border it is a fact that all travel to the rest of the country has to go through a few highways, a few geographic funnels. If the geography was different and it was flat and heavily populated, the highway checkpoints wouldn't be effective because you could circumvent them with street roads. Having a second check point after the border creates a funnel where the contraband must go through. While it is possible to around some of the East West highways it is not possible to avoid the North/South highways and they get a huge amount of contraband even with the cartels knowing that they are going to be checked. So effective have these checkpoints become that the cartels have even tried to paint their own FEDEX trucks, and in one case paint their own Customs vehicle, which to their bad luck got a flat tire.