Pf--This is a HORRIBLE thing that is happening to you and my heart does feel for you man.I myself have lost many a jelly filling to some idiot with a sand shovel.(I am from Fla.it only snows in Miami.)I do know of a possible solution.
Since you may never be able to curb the human desire to ruine someones doughnut.you may be able to curb the human.Simply take your snow plow on the sidewalk and instead of snow bumps that people have created for you create people bumps and then even though you may still spill some jelly at least it will be because of your hystarical laughter.
Call me from prison and let me know how it went.

__________________
It was me,I did it.....
I killed you with buttons and bows....
all those clothes......
while you slept.
Rodger Waters