If you've downloaded the latest beta version of iTerm2 (3.0.0), you may have experienced a popup warning like:

The bell is ringing a lot. Want to suppress all output until things calm down?

That's not too bad, but the buttons to suppress it and future warnings don't actually do anything. This is a major pain in the ass, and breaks usability for me, as it covers the entire top two lines (or so, depending on your font size).

To get rid of this thing, simply go to Preferences -> Advanced and set Suppress offer to silence bell when it rings too much to yes.

Easy. Now it's time to get back to work, uninhibited.