In Texas, there really aren’t dive trips that are accompanied by a DM, unless you specifically pay for a tour or course. I’ve been on dive trips in the Gulf and if there is a DM on the boat, they have gotten in the water. Unless the DM is also the boat captain :)
On dive trips in Cozumel, the DM’s with Sea Robin Cozumel have always got in the water to show us the cool stuff and to lead the dive.