it's actually both the ada and hipaa. i don't have the hippa cite but for me it all depends on the screener. most of them have been very nice (esp bos this past w/e ^) tho occasionally one will ask if i can remove my shoes where i will very politely tell them that i can't. if the screener is being a "jerk", i will tell the screener that they are not allowed to ask me that quesiton and if i am further quesitoned, i tell them to look it up both under the ada and hippa acts. that has solved the problem for me in the 2 situations that warranted it and in both cases, the screener called for a supervisor who sided with me.