I believe this is true.  I have seen so many people acting extremely self-righteous and ignorant or evasive while crossing borders and I have never seen ONE such instance where their attitude helped their situation in any way.  For somebody like that, a secondary screening is no surprise.  In fact, to me it is even expected.

No way does it mean I would travel with a lot of money in my phone Cryptocurrency wallet, but in my opinion ideally nobody should ever cross border carrying ANY hint about owning cryptocurrencies.  This can easily land anybody in either unnecessary suspicion or unnecessary trouble.  Now imagine you are crossing into another country where just recently a terror attack happened and you are the first to give hints about using Cryptocurrencies.  Why potentially put yourself on a list?

There are so many ways to avoid this.  Hell.  If you cross borders planning to carry and use a stash of over a hundred thousand, simply purchase a cheap Android device after crossing the border to use as a payment device and then discard the phone before leaving the country.  If such large amounts are involved I would make sure I find a way to hide the seed extremely well until I cross.  Sew it inside a wallet.  Encode it into a piece of clothing.  There are many ways to do it.  Crossing China, the United States, Russia or any other country with more serious or stricter border rules while having hundreds of thousands on your phone and not even declaring it, that is simply asking for trouble and even I would suspect somebody in that situation if I was a border patrol.

But then if one does not declare their amounts before crossing, what is the point of even carrying that much on themselves.  Unless they are trying to flee their country and to do so they have to cross countries like China, there is no point in my opinion.

Anyway.  The best thing to do is arrive at the borders in such a way you are least likely to be suspected and thrown into unnecessary trouble.