I got the same question when I was in the US during the anniversary of the assassination in 1993, and gave the same answer. I was born in February 1964.
But it seems like she’s desensitised to all the amazing things happening around her. While it would be be an interesting thing, ultrasound, unlike telekinesis, doesn’t violate any laws of nature.
I remember that some early TV remotes used ultrasound. Actually, I remember actually being able to hear it for some of the buttons. But I’m pretty sure that until recently, most remotes used IR. So-called universal remotes do, but as far as I know, can’t duplicate radio remotes.
But for garage door openers, you’d want a solution that can’t be duplicated. You don’t want it to open from someone else’s remote of the same brand.
Wi-Fi is possible, but you don’t want it to depend on a Wi-Fi router being within range? Of course, there’s also Bluetooth. But all are variations of radio. You just need a solution that’s paired to one door in particular.
Further thoughts. I said before that I don’t know much about Annie from before she started appearing in Dick Tracy. I’ve seen the movie, of course, but I know that movie adaptations often change things. Still, Annie’s parents have been unknown since the strip started, so long ago, right? It seems a stretch to have them turn out to be someone Warbucks and Tracy actually knew, and no one even suspected.
Marigold feigns ignorance when asked that question.