That's not surprising. The Netherlands have a long history of producing quality XTC / MDMA and are one of the biggest XTC exporting countries worldwide. Furthermore, given the relaxed weed legislation a lot of marijuana is produced here.
A 99 euro vacuum food saver will get you a long way in sending drugs worldwide. Combine that with some clever packaging and the chances of it getting caught at customs are pretty small.
Heard the same from friends - they were sending meat products that were a little on the grey side of import rules across a border. Vacuum packing + bleaching it overnight seems to keep the sniffer dogs away. Whether that works for drugs I can't say though.
Dealers use moisture barrier bags that are heat sealed now as apparently dogs can detect vacuum sealed bags though unclear if it's outside contamination, like somebody putting together a package in a room full of weed shavings or smoke.
Both heat sealed and vacuum sealed are air-tight, so that difference should be a non-issue. Its the stuff sticking to the outside of the bag that might be an issue. For meat I'd imagine bleach should do the trick...no idea what you'd need to remove drug traces though. Not a skillset I plan on deploying anytime soon so didn't research it.
Is that reliable though? I'd imagine the DEA is more likely to investigate a dealer declaring their location as Washington DC than one declaring Netherlands. So their is a definite incentive to falsify this.
But a buyer from the US is far less likely to order from the Netherlands since international mail goes through customs and there's no 4th amendment protection on them at all.
The majority of the buyer are going to buy on feedback. And a US supplier using fake Netherlands location is likely to get good feedback based on fast shipping (seeing how its fake Netherlands) and gain the benefit of the "positive" Netherlands connotations (Hollywood's view of the Netherlands in the average person's eyes).
4th amendment - true but not relevant to an environment dominated by non-lawyers and buyer's reviews I think.