Are planes in the habit of carrying much more fuel than they need, just in case they will weigh too much when landing, in which case they dump the fuel? No. In the inverse example, we don't put extra load on servers in anticipation that load goes up, just so we can dump the extra load and put it back to where it would have been had we not had extra load. The idea is moronic. It is literally the same as putting lead in your servers until you have to dump it, just because you can. Real admins have alerts on their servers to tell them when they will need additional capacity.

Incidentally, fuel dump systems were initially added due to a rule by the FAA that a plane's structural landing weight not be exceeded by its takeoff weight. Many commercial planes never had this problem, so dumping systems were not installed. As a result, most planes just circle until they've burned up enough fuel, or land anyway overweight. You could dump fuel to lessen the chance of explosion, but only if your plane is equipped with a fuel dump system, and such incidents are so rare it's not even a safety consideration.