I've had one of those packages arrive, with the terse note; if defective return "unopened" with full details of the fault (paraphrased in case it identifies the manufacturer) Unfortunately, on opening the product was found to be faulty. I have many qualities but clairvoyance is not one of them!! Fortunately, it is an Amazon purchase, and they are dealing with it...
Experience; is something you gain, just after you needed it most.
When faced with two choices, simply toss a coin. It works not because it settles the question for you. But because in that brief moment while the coin is in the air. You suddenly know what you are hoping for.
And don't forget that under the Distance Selling Regulations, you have the right to return them within 7 days anyway, whether they are faulty or not. (unless of course the goods are one of the exceptions; manufactured to the customer's specification, food, flowers, magazines etc) John