XML isn't anymore secure. There's also a verification process when you submit flash based material to certain media -- In terms of games clearly they're going to have checks for when you try to utilize addons, so it's not like someone can write a flash exploit, then upload it to FFXIV servers lol, people would have to download it and obviously you wouldn't download something from 8829.notgoingtohackyou.com, but you would from a site named ffxivpro.com or yellow grimlin, i.e legit sites that are officially recognized by Square.