I don't think it's strange. Even in public restrooms, I also do that. I use toilet paper to cover the lid. Even in someone else's house, I also do that so that. When there are guests using the restroom in our house, I also rinse the lid with detergent and water, and even disinfect it with alcohol to make sure germs are really dead. I just want a clean restroom filled with adequate supply of water because I cannot stand a dirty one. Because I cannot guarantee the cleanliness of the restroom of another house, toilet paper comes in handy.