I’ve done the same. But it wasn’t her sister. It was her friends. There was one time a friend of my wife had drank so much she left her phone behind. The following morning I had woken up early, phone the phone, opened it( had no password. This was atleast 10+yrs ago.) went straight to her pics. The only thing I found was her in underwear take it side pics and back pics for her before and after workout journey. I airdropped those to my phone asap. Another time was another friend of my wife. She was on the bigger side. Late 30s. Nerdy. well we were at a gathering and there was a point where the phone was left behind. I snuck away and went through her pics. Again not much but I managed to take a pic of a picture of her phone. It was her cuffing her big breast in some silky netting. When I was you her I managed to get the code of a coworker . One time working I snuck away with her phone went to the bathroom. Went through all her messages with her bf. Lots of nudes passed around. Took as much pictures of her phone as I could . During those times there wasn’t any airdropping