Speaking of those types, I flew with an LCP recently at our shop. We were United in everything we did, except for the APU.
First leg, we landed, cleared the runway, and I started the APU. He reached up, turned it off and said he wanted to save fuel. Umm, ok? A couple legs later, after landing in DEN, I waited and asked him if it was okay to start the APU as we were approaching the ramp. He said no and then told me roughly 10 seconds later that I could start the APU.
His goal was to time it so we pulled in the gate right as the two minute warm up was finished. It was 97 degrees and he was more worried about burning 100lbs of gas than paasenger comfort.