I would say silly more than anything. I doubt the distance gained is going to amount to anything beyond a waste of time.
BUT, having said that I would also add that if the shot is set to cause a certain difficultysuch as shooting over,around ,through,beside something. The bending of the flag to avert such a difficulty is a violation of the sportsmanship rule as referred above. At the point such an action causing the removal of a level of diifficulty,could be cause for disqualification as un-sportsmanlike conduct.
In a situation such as this, no points are given for ingenuity. Shoot it like it was intended.
ken12