Op as others has commented already, percussion instruments certainly do have a pitch. For a very obvious example of a well known tune, check this video from 5 minutes 30 seconds of Phil Collins performing in the air tonight. It's very obvious that he's got his drums tuned so that he can play a melody.
My reason for stipulating that is that lot of people saying it do so either from ignorance (they simply don't believe/understand that you might not be able to opt out) or on the basis of outdated information, e.g. "I bought my TV ten years ago and never had to do this". Your experience being in the recent past I guess I could try this as a sale stipulation point, thanks.
Not seen where protected categories are mentioned but they aren't vague. The evidence will presumably be that she was thrown out/barred based on an automated camera recommendation. This will be on record and thus she can show harm. The security guard apparently gave a reason for ejection at the time, ditto. What can the retailer say? "Oh someone else told us she was someone else your honour"? Most likely they will try to settle out of court.