I knew there was a reason I avoided this thread
Meniere's disease, which you should know how to spell if you have it to the point of disability, should not affect your driving ability although it may affect your ability to pass a field sobriety test. If you got out of your DUI based on that you also open yourself up to the other implications that go with playing the undeclared disability card and the issue of driving and/or teach while impaired.
The school owns the computers and anything you do while using them, there is no violation involved. They could have examined your computers at any time. Now you have played the disability card, they are well within their rights to investigate your claim since it affects your ability to teach and their risk in various ways, all of which they are mandated to protect. You are reacting like a guilty person, with something to hide, rather than a person with a disability. If you really had Meniere's disease, no doubt you would have been claiming problems from it for some time. Guess what? They may request information about your medical record, you will be asked to sign waivers and your refusal to sign them will play a role in how all this turns out.
So your slick DUI defense may have caused you more problems than you think and your disability claim may also be denied even though you got off your DUI based on it, which will leave them with grounds for dismissal that your union will have no grounds to fight. Your stellar past will have little effect on your future unless there is substantial documentationthat you indeed have a qualified disability. I suggest you read up on ADA accommodations and disability law while you are not working.