I had the same problem with a brake buddy and was unlucky enough to destroy the front brakes, calipars, bearings, etc. The wireless alarm did not warn me that the break away plug had come out. Hopkins asked me to send the unit in for inspection, and surprise, nothing wrong. To make a long story short, after a discussion with the management there about my intentions to pursue, they agreed to pay for the repairs and sent me the newer model brake buddy with an enhanced alarm system-which by the way only works intermittently.
Not able to trust their equipment, I ran a wire off the brake light swith in the toad directly to the dash in the motorhome, and built a little alarm box with a buzzer and light I got from Radio shack. This works everytime the brake pedal on the toad engages for any reason.
I think the wireless system they have probably works ok on shorter rigs but mine is 40 feet and the toad is a full size pickup. Some times the alarm works ok, other times it sits mute. I suppose outside interference could affect the functioning also.
I was disappointed with Hopkins but they eventually made things right-but it was a scary experience and a lot of hassle to convince them to do the right thing. Good luck, but be careful with brake lockups-my pickup was very close to onfire by the time I figured out the brakes were locked by the brake buddy (without warning).