The chances of someone bricking using menuhax is practically no existent, The installer only installs something to your theme data, which allows it to trigger before the homemenu loads. It is impossible to brick messing with theme data. I pretty sure no one has bricked using menuhax, as it doesn't let you have complete control over your console, and if anyone had bricked, they were most likely messing with things when they had know no idea what would happen. The only real possible sencerio that can lead to brick in menuhax is if you mess with your power and wireless leds. No software uses the leds, so you are almost %100 safe. Don't worry, nothing will happen if you only use regular homebrew apps, like emulators, games, utilities, and tools.