He had a little more hassle than I did. Only a little:
So back in July I decided to give it a shot. If you’re a US citizen/permanent resident, Dutch citizen, South Korean citizen, or Mexican national, you can join the program. (Canadians can join via the Nexus program.) I went online and filled out the extensive application. I mean, this thing looks at your history going back for several years. It requires previous residences, everywhere you’ve traveled, and more. Once you finish filling it out, you pay the $100 fee (regardless of whether you get accepted or not), and then you wait.
It took one week until I received an email saying my application status had changed. I logged on and it told me that I had been approved for an interview so I just
needed to schedule one.
The big day came, and I prepared for a grilling. I was WAY over-prepared. I showed up at the Bradley Terminal at LAX and they told me to take a seat and wait. I saw a lot of people waiting there, so I was afraid it might take awhile, but I was wrong. Within 5 minutes, they had called me and another person to go back. The interview between me and the Customs/Border Patrol (CBP) officer went like this:
CBP: Have you been to Canada in the last 5 years?
CBP: Have you been to Mexico in the last 5 years?
CBP: Ok, you’re all set.
I’m not exaggerating at all. It was that quick.
My interview in 2010 ran about 10 minutes, but it was no big deal. They stamped my passport right then and I've had easy entry to the US (and easy trips through airports) since.
It's worth signing up for.