I was oversold when I acquired ADT services. The glass cracking devices cost me almost $1500. Their price to me was significantly higher than published ads and mailers. The glass cracking devices sound the alarm if you sneez and/or drop the soap in the shower. I may recommend them but not to my friends.
The only thing I did not like was they had the volume up all the way and my dog freaked out. Also I had to figure it out myself. No booklet and I had to call the support became they had the exit set at 60 seconds which is too long so they put it to 45 seconds. The installers should check with the customer to see what they prefer instead of just assuming.