Especially for X10, a safety mechanism folks have used was to put two switches in series on different house codes so that the chance of a spurious powerline signal kicking on the fireplace when it shouldn't is greatly minimized. On two house codes so the "All On" doesn't trigger the fireplace when you meant the lights. With a software controlled system, easy to turn both house codes on for the romance. In my mind, worth the additional $30.
Now, with Insteon / UPB / Zwave, maybe not as critical (but probably still a good idea) due to their higher reliabilty and imunity.