Seems to be the case in Belgium, Germany and France.
However, if you use boxes smaller than 3cm, and you drop them in the mailboxes of your national postal service, no-one is going to ask you what's in it ;-)
Anyways, sending cash is forbidden in almost all European countries anyway ;-) (except by registered post)
i wanted to send it in the smallest airpackt 11 cm X 12 so when i register it then i can send it right
I don't very rarely send coins, but I have some sent to me commonly (some even actually by Mathieu). They have always arrived in packages (mostly in the shape of padded envelopes) and I can't complain to much about the shipment costs I'm charged. Didn't notice I steep rise since the 1st of January either.