I just got back from a conference in Las Vegas. At the airport, the Army Reserve troops are carrying M4's at tactical ready. Nothing special about them--other than the fact that they all had the look of new, unscratched finishes. No RIS, no BUIS, no lights. Just the M4 handguards, a detachable carry handle and a 30 rd mag.
I talked guns with one of them and he claimed his unit carried only semi-auto carbines. I didn't think it was the time or place to press him on this and I wasn't about to ask him to let me see his weapon. He commented that only the border patrol carried full auto carbines, so that led me to believe he considered burst fire as 'semi-auto'.
Flew back to San Jose, CA to find the reservists carrying well used M16's with triangular foregrips and no foreward assist.