On my JellyBean Galaxy S2, I can partially disable them from the application manager:

Partially because, although there is no longer an icon on the notification bar, the sound notification still occurs.
Now, on my Galaxy Tab tablet, still on ICS, I can't disable notifications at all, as it's not an available option in the application manager:

All other Android apps I have ever seen have their own "disable notifications" function. This is really needed here.