Interesting.
So if one carries a Glock 8mm in a holster and the police don’t see it ...
Frankly, there are BAD areas of DC (mostly east), MD (east of DC), VA (older parts of Arlington, Alexandria, etc where the droves of illegals congregate and commit crimes), you are insane if you don’t violate in DC and protect yourself.
If someone draws down on you, a knife or lesser forms of protection are worthless.
No-one would see it, because it doesn't exist!