So let me ask you: if you bring your car to the mechanic and say "I need the resistor replaced for the fan speed knob", and then they call you and charge you an hours labor for a diagnosis that the resistor for the fan speed knob needs replacing, is that ridiculous?

And if this same mechanic re-armed your car alarm without asking when you brought it in for repairs, and now you want it undone (because you never asked for it in the first place), and they want to charge you a diagnosis fee, is this not, too, ridiculous?