Originally Posted by NickW

I have a new L-1 visa in my passport with which I will be entering the U.S. for the first time soon. Is there any reason to believe it would be a mistake to take one of the LCY flights that has immigration pre-clearance at SNN, e.g. BA1?

I assume in principle the exact same process would occur as if I arrived at U.S. CBP in JFK, but a sanity check seemed in order.