this all comes back to insurance and liability. it's getting tougher out there. If something happens to a diver at 70 feet and they were only OW...well, it gets ugly fast. We never should have allowed lawyers to dive!
As for nitrox, requiring nitrox for all divers also lets the op keep a shorter SI. And that allows for some faster turnaround on trips. An additional 10-15 minutes is a lot of time when it comes to boat unloading/loading, setup, etc.
I recently had an incident during an Intro to Tech class. Some people think that class is a waste. Student was great in the pool with skills but almost took me out at 85 feet (a story for another day and thread). At the least we learned that he would need a lot more work before moving on to deco procedures!
As for nitrox, requiring nitrox for all divers also lets the op keep a shorter SI. And that allows for some faster turnaround on trips. An additional 10-15 minutes is a lot of time when it comes to boat unloading/loading, setup, etc.
I recently had an incident during an Intro to Tech class. Some people think that class is a waste. Student was great in the pool with skills but almost took me out at 85 feet (a story for another day and thread). At the least we learned that he would need a lot more work before moving on to deco procedures!