I read a story last year about a lady out in California who had her T@B stolen from a gated storage yard in a nicer community. The cuteness factor combined with the ease of hitching it up and carrying it away were all causes to it being targeted by the thieves.
So, many of us T@B owners now take a few added steps to deter would-be thieves. These solutions won't prevent a determined criminal, but will certainly make the T@B more of a hassle to steal than other nearby trailers.
The first solution is a 2 5/16" Gorilla Guard coupler lock. The T@B comes with a small coupler lock already, but it's not solid as a Gorilla Guard.
The next solution is a hitch lock. This combined with the T@B's coupler lock ensure that your T@B can't easily be unhitched and stolen while you're at a roadside restaurant for lunch.
On a related topic of safety, many of us augment the rear of the T@B with extra center reflectors or light strips since the standard T@B tail lights are so tiny. Hopefully it can prevent a weary interstate trucker from plowing into the back of my T@B because they didn't see the lights on my trailer.