At its base, this is how Dekaron works. It's a highly competitive pk/pvp oriented mmo, people will always try to poke in an advantage over others. But of course, if you wanna sleep better at night, you can make an in-game announcement reminding people to read the upcoming patch notes. Or a mail in game.
Unfortunately only a small portion of the community actually uses our forums, so if we released balance patch notes ahead of time people would take advantage of this to try and sell or buy items in game from or by unsuspecting players. This is why we don't release balance changes ahead of time.
We did however give a headsup this time that a Dragon Knight rework is the main focus in the next balance patch along with some minor balance adjustments for some of the other classes.