Dusty Venue Question

Hi...I posted this in sports and thought I'd try here as well.

I have been asked to come shoot a roping (which is big here in Texas). I've been to one outdoor roping to watch once, but not take pictures. And there was plenty of dust to go around. Was a very dry that month.

But I'm told this arena where I've been asked to shoot is kept watered and is indoors. My concern is this...there's bound to be some amount of dust in such a venue...and I don't plan on changing lenses...using a 70-200.

Any advice to protect my camera outside of not going at all?

Is this the f/2.8L IS or f/4L IS? They're weathersealed. Put a filter on the front and go shoot!

Actually it's the Sigma 2.8...belongs to a friend that is letting me use it.

Take a plastic bag that fits nicely around the camera and lens and put the camera in it with the open end of the bag facing down. Screw the filter onto the end of the lens over the plastic enought to cut the bag. Take the cut piece out and screw the filter back on. Good rain & dust resisting trick taught at a Nikon course.

Don't forget a lens hood after putting on the plastic bag, etc.

Just don't change lenses.