I arrived at SEA on Thursday afternoon at around 4pm. No queue at immigration. I spoke to the officer and explained that I had conditional approval for GE. The officer asked a few questions about this journey and took photo and finger prints before handing me over to another officer for the Enrollment on Arrival interview, which started 5 minutes after I sat down in the processing area.
The second officer only asked why I had applied for GE, but other than that, took photo and finger prints and I was approved. Officer was very polite and provided some useful information on procedures and the obligations of participating in the programme. I was provided with my KTN immediately and got my confirmation email a few minutes later.