I can only speak for our company, but we purposefully designed the BitBox02 to look like a regular USB flashdrive or a microSD card reader. It doesn't have physical buttons on it and instead uses capacitive touch sensors on the side. There's a small logo on the front, but that could be anything really. The screen is an OLED behind tinted plastic so you can't tell that it's a screen really.

I've walked through TSA multiple times with a bunch of them in my backpack and nobody has ever asked me about it.