If you mean arguing with the mechanic, not advisable to upset a cook or a mechanic. He is doing fine with checking the battery and starting it. He needs his charger or doesn't want a cord in his way or does not want to be told what to do. It's OK. If you mean some other argument with someone else, Trickle chargers prevent sulphide build up, this should extend life but they can be bad for a battery if they do not have a automatic shut off. Continuously charging a batterry to 100% is not good. Make sure it shuts completely off after reaching near 100%. Year round on several cars? What's the electric cost for that? Buy a good free-replacement battery and you won't need a trickle charger. I guess it depends on your MTBF.
As far as a good web article, you can find yea or nay on anything on the interweb. You can search and read all night on that one. I know you are not trying to be a pain and are just asking him for a favor. Your battery may discharge while he has it, but it won't hurt it and he will make sure it starts before you pick it up. No worry.
