[bluGill]

Easy to say, but this is hard. "I got a box of dust from you". Now was this the lab sending dust because they know it doesn't work, and want to hide their tracks; the receiving lab destroying the sample because they want their own discovery to win a Nobel prize; or just regular managed in shipping? You should be able to think of other reasons that an unethical lab on either end might want to ensure the samples are destroyed instead of tested.

The above can be managed, but it can't be done over a weekend. The lab has stated they are willing to send their working samples out to other labs. However to ensure it arrives safely (avoiding issues like the above) means that you shouldn't even be concerned until two months have passed, and accept reassurance for a few months after that.