heres a view from a pro
If he messes up and you go into a shop to get it fixed
I would charge you double
once for installing
and another for the headache to figure out wtf he did.
Now alarms are for the most part pretty straight foward
But it's the skill you are paying for
what use is a alarm I can reach under your dash and rip out and disconest in 10 seconds
nothing at all
Plus what are you going to do if he taps a wrong wire, ooops there goes the airbag
I don't know what it is about guys, for some reason they think they can install anything
Now your dillema is he is going to take it personally when you tell him no