I don't think its about not wanting people to enjoy their basses, and more about insurance issues that may arise, should they go missing and potentially be viewed as counterfeit. A healthy discussion, I think? Literally wasn't something that occurred to me until reading this thread, and I'm wondering this this is why the many and several Ric copies and similar often ship with a blank TRC with a fake TRC in the case, to avoid counterfeit accusations?
The risk here is the bass being confiscated if the Police need to get involved, rather than returned to Mark, but given insurance isn't involved here I think its unlikely there would be any opportunity for any complaint to be raised, and hopefully Parcelforce will just sort it out with a dash of compensation for the ridiculousness of it all.