The Cars 2 in 3d voucher on the packs of tescos so soft toilet tissues has caused a few problems as the voucher runs over end Aug - end Sep when most cinemas have ceased showing the 3d version by the end of Aug. Cineworlds will let you see the 2d one instead but ring forward to make sure you dont get someone on the front desk who says no.
Also 2 adults and 2 kids - we got in for £12.50 as Cineworld were not sure what to do with the voucher at all so they gave us one adult and one child free where it should have been the kids go free :)