Only on declared worth, as always.
There’s nothing new about the means of assessing the value, just what they do about it.
As far as understating the value, well sure, you might be able to get your sister to put that your Fruit Roll Ups are a gift, big deal.
No actual dealer who hopes to stay in business for long, however, is going to start effectively perpetrating mail fraud because you ask him to.
Could the TW’ese customs call shenanigans on that?
Of course not, nor would they care to.
This isn’t about nailing @Toe_Save’s ass to the wall because he got a couple rolls of hockey tape sent over.