My mom and I were threatened by the security person, because my sister was just standing the wheelchair to get out of people's way. He said of it happens again he would take away my mom's chair and mine. But my mom and I can't hardly walk. - A

Probably not something you should put in the questions section

If your sister was standing on a wheelchair then that is against company policy and a liability to the zoo. It's not allowed within Zoo perimeters. Admittedly, it doesn't sound like this worker got that across very well and if you felt threatened then it's absolutely your right to take it to a supervisor in park relations or customer service or whatever they're calling it this year. If she wasn't standing on the wheelchair then my bad but it sounds like what might have happened and it's a worker's responsibilities to warn you against doing that again. Politely.

File a complaint

I would talk to someone about this that is above this employee

I don't quite understand what was happening with the wheelchair, but if you felt discriminated in any way talk to someone in charge. I go to the zoo every week and everyone has always been very nice and helpful to me. It sounds like it was this employee's miscommunication.

I would talk to someone at the front office about that.