Piggybacking, a technique often used to build credit by paying to become an authorized user of a stranger's credit card account, has been under fire since it first gained widespread popularity in 2007. In practice, the loophole in the credit scoring system works great, which is perhaps why it's ruffled the feathers of so many people that find it unfair and sleazy. Should it really be so easy to dupe the system? Instead of slowly building my credit history one on-time payment after the next, I can simply pay someone to add a credit card with a high credit limit, low balance, and a clean payment history directly to my credit report. And voila - I instantly have stellar credit and thus a higher credit score. Millions of people have benefited from artificially boosting their credit scores this way, and there's no doubt in my mind that many credit repair agencies have made a nice profit from connecting buyers and sellers of trade lines as well.