NASCAR Racing: black flag, draging, harms way

Question
If a driver gets black flagged for a fender draging and he knocks it off AFTER
getting black flagged on the wall should he still be forced to pit

Answer
Usually the answer is no. Though NASCAR can be picky, and if the driver refused to pit for a while hoping it would fall off, that can tick NASCAR off and they can still call them in. If the debris from the car causes a caution, then it doesn't matter regardless. Usually, if the piece dragging comes off, and is out of harms way, they won't keep the black flag on the driver.