I guess the real question is, if you have a valid VISA, you have already answered questions at the Consular office and met their satisfaction, so why any questions at all at immigration?
I'm just very opinionated, but I think the immigration 'questioning' process should consist only of pleasantries while the passport is being scanned. This goes double for people trying to return to their own country. No "What do you do?" or anything like that. Just "Welcome to America".
If someone has satisfied a consular officer enough to cause them to issue a VISA, what is a two bit immigration officer at the border going to uncover?
(No offense to immigration officers)