For most of the scratch off cards that you can buy from gas stations and/or from a lottery vending machine that have some form of game where you're supposed to scratch off to win X, you can just hand the card to the attendant, provided they have the proper equipment(and they should) and if it's a win, they can scan the barcode on the back. No scratching required as the system will tell if it is a winner when it scans. There -are- a few that actually require you to scratch and if you don't match, you lose. Those are pretty rare though.
The thing is, the average person doesn't know that. Hell, I worked retail and even people who did it on a regular basis still went through the process of scratching, when they didn't have to.
As a teenager, Taylor isn't likely to know the specific ins and outs of how the lottery system works so she would be basing her precog when she looked at the cards for: "What happens if i scratch 1, 2, 3 off, etc?" to determine how to make sure she got funds from the cards. In addition to: "If I buy 1 card, what will be the results? Two cards, etc, etc. Til she knew how much to spend to get to cards that would give her something substantial/weren't chump change/worthless.