There are plenty of countries with near watertight customs. Vendors have listed them as "No reship" or no send at all,
The slow march of policies tightening the noose has been slowly put into place over the last 5 years, and we're just seeing the end stages of it,
1. End tax free imports via de minimus: 70% reduction in volume of packages. Much smaller volume to focus on.
2. Require 20x the detail previously required in customs paperwork, and it must be submitted electronically prior to arrival. Patterns are recognized by computer analysis, packages are flagged for extra scrutiny and automatic systems kick that pack off the conveyor belt to CBP officer for inspection. Your previous seizure will be a data element in the "risk score" when your address appears as the recipient in the data sent to CBP.
3. Enforce the regulation that shipping companies must establish positive ID of shipper. Like banking "KYC", know your customer requirements.
4. Make shipping company financially liable for false declarations on packages containing illegal items.
5. Require shipping. companies to deposit $1,000,000+ bonds with CBP for duties and FINES.
6. Impose escalating fines for each package found with illegal drugs, starting at $10,000, rising to $500,000. Additional fines if the sender wasn't positively ID'd.
Now shipping companies in China require ID, and have their own "mini customs" scanning packs prior to accepting them. If they accept packs from companies unfamiliar to them at all.
Obviously some small quantities of packs are still getting through, but the few vendors left sending schedule III Drugs are using multiple shipping lines, knowing as soon as one pack is caught, that line is
burned for them.. Eventually they will run out of shipping options. Sooner or later billion dollar logistics firms will get the authorities in China to do something to the shippers of illegal goods fucking up their business.
It's about finding pressure points and pushing them, using data and AI to focus inspection resources on suspicious packs, motivating shipping companies to police themselves via huge fines, not hand examining every pack like it's 1950.