Travelers should always understand the risks of delivering many items from the same category like makeup, electronics, etc or (example: a lot of smartphones). If travelers are just delivering personal items with limited number, shoppers should always pay for the customs fees upon receiving the receipt. (Traveler has to provide the customs receipt or other legal proof).
However, travelers can be the reason why shoppers are paying customs due to exceeding in delivering items and hence Hitchhiker has the total right to estimate how much should travelers pay and it’s done case by case and can take up to 45 days to take decision in complex cases.
Travelers should be transparent with Shoppers about the other deals they're accepting. If a Traveler accepts multiple packages of the same category without informing all Shoppers involved then ends up paying customs, then HitchHiker has the right to not pay the Traveler Reward (partially or entirely) in order to reimburse the Shoppers.
Hitchhiker will always make sure to moderate conflicts between shoppers and travelers if both parties are willing to help.