A protection plan is like insurance. Insurance companies make money by charging more in premiums than they pay out in claims. It's sort of like gambling in Vegas...in the big picture, the house wins.
So why do people buy protection plans or insurance? I can think of two good reasons. First, people buy them because the cost of dealing with a loss is so financially burdensome that it is safer to offset the risk with insurance. You know full well that the insurance company is charging you more than you are likely to get paid in claims on your house, but you insure it anyway because having to eat the cost of a burned down house would be much more financially disruptive than paying a monthly insurance premium. If your $170 scanner broke, would that put you in a serious bind? If so, buy the protection.
The other reason for buying a protection plan is because you have an information advantage over the insurance company. They do the best they can to assess risk and to charge people that are high risks higher premiums. If you think that you are at a significantly higher risk to have your scanner fail than is normal, the protection plan makes sense. Perhaps you work in a harsh environment or your electricity is really, really flaky.
If neither of those conditions is met, I think you are better off saving your money rather than betting $32 that your scanner will fail outside of the warranty period but during the extended warranty period. It's a bet that is extremely heavily in favor of the protection company. That's why they market protection plans so aggressively.