Posting this because the summary going around does not say what the paper says, and the difference matters for how people here are using it.
The variables that decide how a cross-border order goes are declaration wording, the destination country's import rules for prescription medicines, and whether the shipment looks commercial. Personal-import allowances exist in some jurisdictions and not in others, and where they exist they are usually conditional on a prescription and a quantity limit. The failure mode is normally a seizure notice rather than anything worse, and a reshipment policy is the thing worth confirming before ordering rather than after.
Where I think it is weakest: the comparator does most of the work in how this gets reported, and it is not the comparator most people think they are citing.
What would genuinely help is knowing which of the variables in a cross-border order actually determine the outcome, and which are superstition. Tell me what I have not thought of.
Note on sourcing:
Figures above are from the primary publication rather than the press summary. If a number here disagrees with one you have, post yours and we will work out which of us is reading a secondary source.