It is kinda a crap shoot. Most any kind of a lock or cable with a padlock will keep honest people honest. They will probably protect your trike from joy riding kids. However I really dont know of a way to fully protect your trike in all cases. A bike thief with a battery powered dremel tool can cut thru most cables and locks in under a minute.
BTW after having a bike stolen out of the back of my garage while my wife was tending flowers, I now lock up both my bike and trike in the garage. I can at least show the police and my Ins company that I tried to protect them.
Bottom line here is that I never let my bike or trike out of my site when I am out riding. If I am at a cafe having coffee or something I lock them up with a light weigh cable and padlock. Hopefully it will slow down a thief long enough for me to get to him.
Last edited by rydabent; 10-31-13 at 08:20 AM.