> GiftRocket uses my location to check I’m actually at the pub and
  > when my location is confirmed I get my gift. The GiftRocket
  > amount is transferred into my Paypal account and I pay as normal.

So it's essentially a money transfer between two people but GiftRocket takes their vig and the recipient needs to be at a certain location (or fake the location) to receive the transfer. Depending on the percentage, this could be abused to launder money through the pretense of a gift purchase.