Do you have an ammonia problem?
I have never used Ammo-Lock, since even when I used to do fishy cycles I would do water changes to keep the ammonia down, since the bacteria you are trying to grow needs ammonia to grow. It will hamper the cycle. If there is an emergency of some kind where the ammonia is off the hook and water changes that would reduce the ammonia to safe levels would shock the fish, then I could see using it temporarily, but as a rule it is not a part of regular tank maintenance.
Her intentions are good, though, and I am sure there are plenty of people who swear by it.