It sucks that we have to worry about these kind of things while on tour. But what can ya do.
You know, there might not be that mesh stuff made for paniers, but perhaps there is a market for it. Maybe someone needs to contact the same company who makes them for backpacks and inquire.
Al223 raised a good point. How about possibly taking off the paniers and putting one atop the other then using the mesh. Maybe it could even cover a handlebar bag as well.

Thinking about my touring set up, it seems there are too many things to think about securing. For instance, I have a trailer. Whats stopping someone taking my 280 dollar trailer and whatever is in the sea bag away? I guess I could lock it to the frame when I lock up the bike, but that still leaves the sea bag an open target.
Perhaps something like this mesh can be used in conjunction with the trailer and one could put a couple paniers on top of the sea bag then the mesh would lock over the top of the trailer which would be locked up with the bike.

All this worrying about our goods and then someone will just come by and rip off our saddle, then we'll have to peddle standing up as we look for a bike shop.

Oh well. I'm interested in following this thread, as I want to protect my investment as well. It will be all I have with me!

Dave