Fun fact: I typed "once" into google and the second thing that came up, after "once upon a time," was "once upon a time elsa." It's not just little girls that are crazy about her...
I was talking to a friend of mine who lives in Kentucky, and she's annoyed by it more than amused, and ashamed that the joke started in her state and has now inspired other related incidents, such as a staged arrest of Elsa in South Carolina.
Then the original state had to get in on the action, and the town of Hanahan Kentucky arrested Elsa,
Frozen products are still heavily featured everywhere, unusually so for a Disney hit more than a year after its release. I'm sure the coincidence of two unusually cold winters for the Midwest and East Coast immediately following the release helps fuel the jokes and comparisons (*shakes fist at global warming for not being there when you need it*...)
The original police announcement: