All Roofnests attach to crossbars using 8 M8 nuts. One option is to use what are called security nuts instead of the included standard nuts. These security nuts require a special tool to tighten and loosen.

You would need:

Set of 8 security nuts

Matching security socket

We will say, out of thousands of tents, we have heard of no thefts! Typically it is just not an item that looks too appealing to a thief. Also, in our opinion a thief isn't very likely to sit there with a wrench in the first place and any sort of security device like this can be quickly removed with a saw.