AFAIK GW has a sanity check:
If the launcher/SD is corrupted or the MD5 check fails, you just get a black screen and need to restart.
If the launcher isn't loaded like it should, you just get a black screen and need to restart.
If emunand isn't loaded like it should, you get just an error message about powering off the 3ds and need to restart.
Obviously, if your launcher is magically modified in a way it magically erases the encrypted security checks while magically letting every other line of (encrypted) code intact (including the evil brick code) and it magically continues like that with no other error whatsoever until the evil random-date brick code is activated, then yes, you could brick your 3DS.
Still, your 3DS or GW could also fail at any moment and brick your 3DS, they're just cheap pieces of mass-produced electronics. Anything can happen at any time.
Warning: Please understand. I'm not saying any GW firmware is 100% safe. I could very well be an evil agent from the GW church trying to brick your 3DS. Don't trust anyone, I'm just speaking for myself. I repeat, I'm not trustworthy, act at your own risk.
Edit: I almost forgot the main reason I don't like 2.0b1, it's way more unstable, it fails a lot when loading the GW menu/GW mode, and it also tends to freeze your console when you close a game (and you can lose the save data of the last game you played if you were using the Red GW card).
