Failed Sting Operation

Last month Borders charged me sales tax on a newspaper purchase. I returned today, armed with documentation from the PA Department of Revenue website expressly stating that newspapers are sales tax exempt. Much to my surprise, they didn't charge me sales tax today. I don't know if I should be pissed off or delighted. I should be pissed off that my sting operation failed miserably. However, I guess I should be happy that they didn't charge me sales tax. Maybe they read my blog post from February 20th and wised up!