On the airline I used to work for, there was co-ordination between ground engineers and the cockpit in relation to both air and power. Although there is a check valve on the ground air inlet, we saw several failures of these after we started using ground air as standard practice. The operators of the ground air equipment also warned us that back pressure from the aircraft could damage their equipment.
I suggest that you forward your concerns to management so that they can can sent out memos to ground staff. However, the installation and removal of ground equipment can be fairly labour intensive. I imagine those airlines working on a limited budget may not be able to provide sufficient manpower to follow the correct procedures without incurring delays (the ground handlers usually have numerous other duties to perform)