You don’t have such laws in Washington DC?Funny you should ask. A few years back my wife and I were stuck in Reagan (an airport in D. C.) for a super-long layover. As I'm watching my first ever episode of Archer, I notice the family a row over gets up and walks down the concourse, leaving their bags. Now, I've heard a bit of their conversations as I've sat there, and I gather they're American and probably self-centered and clueless. Or maybe that's what the terrorists that just walked away from their explosives want me to think. Regardless, we're sitting at the gate and there's a gate agent right there, so I put this in the "not my job anymore" bucket.
It's been a few years, but I'll bet it was at least ten minutes before the agent called security. It was long enough that I was about to get up and ask, "ya know, I'm not the super-paranoid type, but don't you think you ought to give the dog a little practice sniffing bags?" The dog and an agent or two show up, give the bags a sniff, and wait for the owners to return. I was disappointed that there wasn't at least a little ass-chewing. I mean, what U. S. resident doesn't know not to do that? And if they don't, how about driving that lesson home?
But anyway, we don't get too worked up about a random bag lying around. Because in the U. S., thus far it hasn't been shown that it stands much of a chance of blowing up. My sympathy to countries that have not been so lucky.