For example, when you roll a dice, you can check that you are not getting four every time. But if you would, could you call it random?
Well, it depends. If I have tested the dice and I've verified that, on average, all of the values have a ~16.66% chance to return, then it's safe to assume it's
random. At least, that's the definition according to Wikipedia:
In common parlance, randomness is the apparent or actual lack of pattern or predictability in events.
I know it sounds paranoid, but I don't know what to answer if one ever made me such question. Like, sure, most of the hardware is very unlikely to have this kind of weakness, but what about hardware wallets? They're designed for solely transacting bitcoins and their random number generator, as in all hardware, isn't
apparent.
Couldn't one of all these hardware wallet companies implement something like that and steal millions of dollars worth of BTC, in just one moment? It would probably be the worst scandal of the crypto space.