When the invasion kicked off, like day 0, SF assets all over the place were ready to bounce and get in there. I know at least one GROM and UK guy who were training their counterparts in case they got told they could support.
But, as others have said, these are more akin to advisors than "behind the lines" active missions. If you don't think everyone has someone backing up the tax dollars they're sending, you're naive at best.