Install on a storm door or the aluminum siding with anti-theft?

My sister just purchased a second generation Ring wireless doorbell. Her only two options are to attach it to her storm door or on the aluminum siding. Her storm door swings out and all products sold that I can find are for inward opening doors. I also heard that installing them on a storm door is not good because of the metal and glass. What about aluminum siding then? Also, with either option, is there an anti-theft gadget. She rents but because of ongoing dispute with her neighbor the landlord is allowing her to install however she has to do it.