Instructions:TERMS & CONDITIONS
1. This voucher is only valid for Virgin Atlantic passengers who have checked in using Online Check In between 7 March and 6 May 2007. 2. This voucher must be redeemed by 6 May 2007 and will not be valid after this date. 3. This voucher cannot be used in conjunction with the £5 OFF WHEN YOU SPEND £50 voucher featured in the Retail Therapy Little Brother Booklet. 4. Only one voucher may be redeemed per passenger. 5. Only one voucher may be redeemed per transaction. 6. Only one voucher may be redeemed per flight. 7. Only valid for products purchased from Retail Therapy. 8. Voucher only valid for purchases of £30 or more. 9. This voucher is not valid for purchases of Upgrades. 10. Only valid for onboard transactions and is not redeemable for goods ordered prior to your flight. 11. Voucher valid for pre order of goods purchased onboard for collection on the return flight. 12. This voucher is non transferable, has no cash value and may not be sold or bartered. 12. This voucher must be handed to a member of Cabin Crew once purchase has been made. 13. This offer can be withdrawn at any time. 14. These Terms & Conditions are subject to English law and non-exclusive jurisdiction of the English Courts.
However I dont think they check whether you check in online or not.