Sinsull - New York got aggressive because NYC folks (who have to also pay CST as well as SST and.. they pay CIT as well as SIT) had these elaborate systems for calling purchases in to NJ vendors just barely across the border who were essentially middlemen. then, somebody from NYC would pick up all the merchandise and redistribute it back in NYC - mostly high ticket items such as electornics, luxury jewlery and furs.

then there's the thing where NYC jewelry stores will mail an emtpy box to a NJ PO BOC and let you walk out with the Diamonds sans any sales tax. (a felony for both buyer and seller)