Walking back to the fence after every point is taught to disrupt your opponent.
Its sad that kids are taught to use unsportsmanship tactics to win matches.
You don't think that the parents at junior tennis tournament most of the time are not the issue? I'm telling you. Most of the time, when the parents think there's an issue, the kids don't. The parents make a big deal out of EVERYTHING. A close call on the opposite side of the court that they are sure that their kid hit six inches inside the line that is not. The other kid is receiving coaching (according to the other kid's parents), but they are not. The list goes on and on.