Neighbors left garage door open since 8 pm and now it’s 3 am

Should I ring their doorbell and let them know? They have a lot of valuable things in their garage and I know they are people who usually keep their garage closed after they get inside. It rubs me the wrong way to know that anyone could possible walk in and steal or even harm them. Though I never spoke to them. Is that weird and is it too late to do such a thing? I just came home from the club so that why I knew the time.