The only risk here is that the addressee does not accept the package and you are out for all of the postal charges, Insurance charges and the COD charges (the package will be returned to you).. or the buyer's supplied check is not good, but then you usually have legal recourse.
All of the advise about secured payment and registered mail is
excellent. I have one more little bit of experience to add: be sure
to attach the COD form firmly, right along side of the address, and
the registered label. Even with those precautions taken, I had a
package delivered without the COD amount being collected. The
addressee knew the package was being sent COD, but accepted it
without any comment to the new / temporary carrier. Seems as though
there is some kind of mind-stall when it comes to dealing with
unfamiliar procedures on the part of some postal workers-the
receiving post office claims the carrier never saw the COD form. I
checked with my post office, but the only recourse they offered was
to reimburse the actual additional postage for the COD service which
they hadn’t provided. After all, the package was delivered on time,
intact. Perhaps this was the exception, but I didn’t seem to have any
recourse while the 2 post offices were trying to sort it out. The
addressee did come through in the end, and paid the enclosed invoice,
so the postal service was off the hook, after they refunded COD fee.
I have used registered mail for many years, and without any problems.
This has been the only issue I’ve ever had using the USPS.
Melissa Veres, engraver