Pro level cards, if you're current that's good - being a Pro doesn't mean I'm giving you a less experienced diver (the complete opposite) but it's nice to know incase something bad happens and you need assistance. Hopefully the professional respect is two way
Buddy matching is without doubt the hardest thing a dive centre has to do, and while it's not ideal to buddy 2 divers of disproportionate experience, sometimes it's unavoidable given the divers registered.
Diving Dubai's comments are consistent with my experience. I got my first professional card 16 years ago, and I have always shown a professional card in these situations. I have
never been intentionally buddied with a weak diver because of my professional status--quite the opposite. They try to get me with the best divers on the boat. Believe it or not, they want instructors to be happy with them, come back, and recommend them to others. Once in Cozumel they screwed up and put me on a boat with 4 people, a husband/wife team of pros and a raw beginner. Of course, that forced me to buddy with the beginner. When we got back, the owner immediately gave me an apology and a full refund without my even mentioning the dives.
Once diving with a big company in Hawai'i (Jack's Fish Locker), the big boat was divided into 3 groups based on our certification levels. When our group got together, someone from the company explained that they were training a new DM, everyone in our group had more dives than the new DM, and we should just have fun and stay reasonable close to him. The other two groups were all beginners. We splashed first and got out of the water last, after a really great dive. I wonder how many instructors were in the two beginner groups, smug in the knowledge that they had fooled the company by only showing a basic card.
This past winter in Florida I was forced to change dive operators. I showed my trimix instructor card for a basic reef dive. I dived with that company for the rest of the winter, and I was given complete freedom to do whatever I wanted to do on the dives. They just asked me to be back by the maximum dive time, which, of course, I always did to the minute.