We (CCW-ers) only get upset about people knowing because then they raise a stink about it. Where I live, there is a huge proliferation of guns and hunting, so even if people knew they'd shrug and go about their day. In a major coastal city (say in California or the New England areas) everyone would flip a shit, call the cops on me, and accuse me of being a baby-killer.
Why not do both at the same time? Power draw. A microwave can take over half the available load on a standard household circuit. Most are wired for 15 amps before the breaker starts tripping. Heating elements are just as power-hungry, which is why you typically see electric stoves on a dedicated 240V, 20A circuit. I would guess most houses do not have the wiring to support this.
That's why responsible gun owners lock their guns up, not hide them. Furthermore, they educate and teach their children about the proper handling and use of firearms (which progresses from "don't touch and tell an adult" when they're very young to actual proper handling and usage when they have shown significant maturity and responsibility).