Sienna Tries to Have Her Cake, Eat It Too

8/11/2008 9:45 PM PDT
One day Sienna Miller is courting the paps in Malibu, today ... not so much.

Sienna was at a gas station in Malibu this afternoon when our photog tried to hit her up with a few Balthazar questions -- and she wasn't having it!

To her credit though, she did come to the aid of a kid who got caught up in the pap crush -- though the kid was trying to snap a pic of Sienna himself.