I haven’t had any problems when I’ve chosen to disclose. I find that it’s often a great time to educate. When I told my current boss, she thought that it was a mental health issue. I told her that I am actually quite well adjusted, I just have what is believed to be a genetic neurological disorder that can affect the balance of brain chemicals and make it impossible for me to tune out distractions or remember to complete certain daily tasks. It’s really not that different from diabetes. Just like a diabetic has to avoid sugar at certain times, I have to avoid the internet or I could go into an inadvertent comatose state. 
I don’t agree with the idea of a mandatory IEP though. IEP’s can detract from the validity of the graduating document and are commonly regarded as a “dumbing down” of regular coursework. I do agree that there needs to be more understanding of how the ADD brain learns effectively and some consideration made for that. In addition, ADD children should be considered in classroom design. Right now there is WAYYYY to much distraction available in a primary grade classroom. Move all the displays to the back of the room. The front of the room must be plain. Sit the child in the front row at all times, and make sure that there are no windows within line of sight.
There was a test case in a Toronto school where children were given yoga balls to sit on instead of chairs. The benefit to something like this would be twofold. It would allow the ADD child a chance to bleed off excess figityness as well as provides some activity to promote better health.
Now in typical ADD fashion, I have gone completely off topic into a soapbox rant… 