I regularly picked up planes at the gate in Calgary, and taxi'd them to the hangar or to a holding bay to do power runs. I held approvals on F28, and Dash 8s. When you were done, you taxi'd it back to the gate. At another company I held ratings for 737s. I work with a few guys that had run up authority on helicopters. I don't think a pilot would Know how to do a runup and rigging checks on most of the planes they fly. But I don't think I could land a jet coming out of the clouds, at night, in the snow, with ice fog, and 100 plus people in the back. Taxiing is the easy part. The only things about taxiing I didn't like was when I had to go to a different airport to fix a plane, and try to find the map of the airport, and the radio settings.