Once when I worked in bookstore a man came into the store and faked being deaf. My coworkers and I jumped through all kinds of hoops to accommodate him and spent a lot of time writing notes back and forth to help this customer find a particular type of book he said he was looking for. After half an hour of scribbled notes, fetching books from the stacks, and iterating towards what he was describing the man bust out laughing and declared "Hahaha! I'm not actually deaf!!" and walked out without buying anything.
I felt stupid and annoyed that he had wasted so much of our time. Not only did that man's behavior distract us from other legitimate customers, the experience left me feeling guarded about whether to accept people at face value. I never encountered any other customers with hearing disability while I was at that job, but I'm sure I would have had skepticism from this hoax experience in the back of my mind as I tried to help them.
You are not helping anyone by pretending to have a disability.