Packing Instruction applicable to UN3363 Dangerous Goods in Apparatus/Machinery is PI 962. Instead of saying “UN specification packaging is forbidden for packing UN3363”, the airline should have said: “UN specification packaging is not necessary”.
You only need to satisfy the stipulations mentioned in PI 962. The General Packing Requirements of DGR 5.0.2 must be met, however it is not necessary to follow 18.104.22.168 (Packaging Test Requirements), 22.214.171.124 (APIO requirements), 126.96.36.199.3 (Orientation), 188.8.131.52 (Packagings for Liquids).
Special Provision SP A48 states packaging tests are not necessary. Any strong packaging that satisfies PI 962 is acceptable. From a quality standpoint, the use of UN specification packaging is welcomed because of its strength although not a requirement. There is no need to hide the UN specification marking, but unnecessary questioning may occur at time of acceptance.
Unnecessary questioning may also occur later at time of unitization when the airline workers may spot the use of UN specification packaging. To avoid such unwanted questioning, may be someone started to hide the UN specification marking however such is not necessary.