I did - as did others on VJ - and it was a breeze; for me at least.
The lines for immigration aren't too bad even when busy (unlike Raleigh/Durham which is a TINY place and very HOT), and the immigration folks I ran into on the pre-K1 trip and with it, were polite and not too scary, lol.
AFter getting thru immigration (as if you were just visiting) they direct you to go to another room AFTER you pick up your luggage - they took my MBE and passport, and gave me a laminated number card. I had to show that to the person on the cutsoms gate, so I went to the right place for 'processing'.
The actual 'processing' itself took 5 mins - tho I had to wait to see someone for about 10 - 15 mins.
From there I just went out another door right into the airport arrivals waiting lounge