I'm not sure if this is a serious question or not...
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Everyone has pretty well covered whether or not you should have your own gear.
In regards to the OP's concerns of safety by not having the same gear as the students; I personally believe you are giving the student an advantage by not using the same equipment as them. It reinforces the need for a buddy check so they can familiarize themselves with different gear configurations. Once they leave your care it will be very rare they find themselves diving along side someone with the exact same equipment set.
It would seem I cracked pandora's box a little bit here.
Clearly not everybody agrees, especially LDC owners and their employees.
So, I'll go back to the original issue that brought up the topic, which is in the OP.
I feel a student and instructor should be wearing the same equipment for THE STUDENT'S sake (whether or not the instructor owns his own equipment). I could care less about what the LDC owner's profit margin is. That being said, I haven't seen a valid argument so far as to why and instructor should have his/her own equipment as a prerequisite to teach (besides an LDC not having enough equipment, but I wouldn't work for a company that didn't have enough equipment anyway).
Also, the stories so far about LDC's requiring particular equipment to work for them is EVEN LESS incentive for a young professional to start making purchases before landing a job they see themselves in long term. It feels a bit like the industry is detaching itself from its future instructors/leader.
Ok, so this is actually an interesting argument.
Make sure I'm understanding you right: it aids the student's learning to be using different equipment from their instructor? By means of encouraging exploration and inquiry?
Now we're getting somewhere.