Foreign currency Xchange at EGHQ
Anyone using the services of the money changer near the metro in EGHQ, be warned......they have a nasty habit of charging you AED20 for the "privilege" of buying your currency back at the same rate (minus the spread I'm sure) in the event that you "change your mind".
When challenged, they say it's a mistake, but it's happened more than once. Makes you wonder.....
Might be prevalent in other outlets too. Check your receipts.