Comment by ErroneousBosh

I have never needed to brake hard enough for ABS to kick in, or at least not intentionally - I don't count wellying on it hard to seat new brake pads, for instance, nor do I count traction control coming in (which uses ABS) under load on loose slippy surfaces.

It's easy to tell when it does - it makes the same BRRRRRP noise it does during the ECU's startup self test from the valve block in the engine bay.