Robert Rodriguez took a page from John Waters and used the marketing strategy of billing his fourth installment in the Spy Kids franchise as a “4D” flick by adding scratch-and-sniff scent cards for audiences. It’ll be interesting to see if this add-on “Aroma-Scope” value increases moviegoing beyond just the 3D higher ticket prices when the pic opens Friday. “When it came time to do Spy Kids 4, I couldn’t just go back and do 3D like everybody else is now. I had to bring something extra,” Rodriguez told the AP. “Just watching my own kids with interactive gaming, you ask them to watch a movie, it just feels so passive to them. I thought, this helps bridge the gap. It’s an interactive thing, almost like playing a game while you’re watching the movie.” In 1981, Waters released Polyester in “Odorama,” while the 2003 toon Rugrats Go Wild also used scented cards. One of the Rodriguez smells is a spy baby’s diapers. “Originally, we didn’t have any really rancid smells, but kids wanted something really stinky in there,” Rodriguez told AP. “It really doesn’t smell that bad. No one’s going to get sick in the theater.” Now let’s bring back “Sensurround”.