Yes, it is quite easy to brick your wii if you mess with untested channels and other .wads. However, if you don't install any you don't need you probably won't brick, and be sure to get the .wad from a trusted source, and other people have verified it works. The best measure of protection are Bootmii, boot2 is the best however ios can help, and Priiloader. Priiloader and bootmii as ios can save like 90% of most bricks, with boot2 you are about 99% unbrickable, only a hardware failure can brick you. Just be careful and don't screw around with a wad manager, and you will be fine.