I would use caution in applying that statement to all airports in the southwest US. Once upon a time (....until last week), I lived in ELP, and when you entered the security line at the airport, there is a CBP officer stationed there 24/7. They are obviously looking for those that might be illegal, and I have seen them pull numerous people aside to check for their papers. This was for all security, not just international.

Funny thing is....the US Government is supposed to avoid racial profiling, but exactly 100% of the people that I saw being pulled aside by CBP at ELP were of Hispanic origin.

Point being, one is always at risk of exposure when dealing with such a high security place.