If you have the Falcon- good news! Your tent latches already lock.
If you have a Sparrow or Condor, we recommend locking cam straps such as these. This type of locking cam strap can also be used to lock your Roofnest to your vehicle and so kill two birds with one stone. For regular-sized Roofnests, we recommend the 11 ft cam straps and for XL-sized, the 13 ft.
We rarely (actually, never) hear reports of tent burglaries though, so you are likely safe without it.