Travellers are being urged to refuse to let airport retailers scan boarding passes, and Money Saving Expert founder Martin Lewis has explained how.
And speaking to BBC Radio 2, Mr Lewis told people exactly how they should handle airport stores' requests to hand over boarding passes.
“What we need to do, if we want to get them to change their policy, is quite simple," he said.
"Those of you who are going away this summer outside the EU, when they ask for your boarding pass, say, ‘No, sorry, I’m not going to give it to you: it only gives you a reduction.
"Unless you pass that on to me I’m not going to give it to you. Please tell your bosses.’”
Mr Lewis said travellers should ignore claims by retail staff that showing a boarding pass is obligatory: “You’re not protecting the sanctity of Britain by giving them your boarding pass – you’re enabling the commercial company to get a reduction on its tax bill.”