Genius. My first thought was something like plywood, but wire fencing never even crossed my mind. And again, never would have thought of the jam nuts applied in this way. Thank you!!

Theft-proof a truck bed soft cover?

I picked up a soft tonneau tri-fold cover for an upcoming cross country trip. I plan on moving any valuables to the cab when I stop each night, but was trying to figure out if there was a cheap-ish option to hinder thieves from cutting open the top and getting access to my things. There are some cross-bars to support the cover, and it's attached by clamps to the sides of the bed. It only needs to last ~4 days, I don't need the "tri fold" functionality of the cover during that time, and can dispose of whatever the solution is once I get to my next destination.

Any ideas?