it's worthless.
if they are not idiots, they can still cost you a fortune and you will lose money for the device too.
it's just a 2 minutes time to make the aircondition work 24h per day even with the keyfob device installed.
all they need is a screwdriver to remove the device's face and connect the 2 cables together.
it works exactly the same way as a light on/off switch but instead of a button there is a fob.
Look at the diagram below. (ok I know. I am a horrible painter)
The green cable is cut and when we press the switch button it's connected so the electricity can pass through the cables and switch on the lamp.
if we open it and connect the two ends of the green cable the electricity will be switched on for ever.
In other words your guests can unscrew your device, connect one cable in just a few seconds. I would have never given 229 euros for such a cheap useless piece of crap. it doesn't even worth more than 15 euros + a few euros for installation