Mother-in-Law

I live with my in laws at the moment unfortunately and yesterday I went to the doctors and I wasnt supposed to be back until 5. It ended early and I got home at 3. When I pulled in my 2 dogs were both running around loose despite how it gets me and my SO upset because they takes off running after any vehicle and its hunting season. I dont want them to accidentally get shot since we are surrounded by hunters and hunting land. She even told me she purposely let them out loose and tried to make it a joke even though i was clearly upset. She had her granddaughter still in the car so if they did take off she wouldnt have gone after him and no one else would have been due home for atleast another 2 hours.  Just as I pulled in she was opening the door for them to run loose and they ran straight for my moving front tires.  Nothing was in her hands and its a double door porch so youd have to do it on purpose.  How can I make her realize that if anything happened itd be her fault? I dont even want her bothering to let the dogs hooked out on their leads. I realize she doesnt have to let them out and does it to be nice but to purposely go against our wishes is BS. She literally told me she let them out loose on purpose because she didnt expect me home so early and she thought itd be nice for them to be free. What kind of bs is that. To let my dog out loose, admitting that she knew it was wrong to do so and she did it because i wasnt around... I havent said anything yet but i want to. I just need to figure out a nice way to do it because plain asking her to keep them hooked isnt working apparently.