I'll echo the response to not worry about it. I rarely use mine anyway because I find it's a real pain to get in there and R/I it.

The common thief probably doesn't know how to operate it, and lets all just assume that Harley riders won't steal from one another. (Yeah, I know)

 

If I was really concerned about it, I'd toss it in my tour pack and lock it.

 

I have a hard enough time getting mine on and off as it is. And I only put it on about once a year.

If it's on - I leave it. 99% of people don't even know they're removable.

 

Id be more worried about loosing the whole seat, 1 Phillips screw and its gone. Granted a locking backrest would prevent that too never heard of anyone loosing their backrest to a thief.
My signature series solo seat's backrest is bolted to the main seat so they better bring some wrenches.

 

I simply use a zip tie around the push button release rod...almost invisible and a pen knife or wire snip takes it right back off...if you can't push that little black bastard up to release my backrest without a fight might be less of a chance of you fiddling with it...I used to do the same when I lived in West Texas to my truck tailgate...they were getting stolen right and left so I just used a big fat zip tie over the bottom rotating hinges, nobody ever stole my tailgate.

 

It's a bagger, lock it the saddlebag and walk away. K.I.S.S.

 

This!!!

I am not a trusting soul.
Zip ties are cheaper than a new backrest and if the wife and I are on a trip, she'll have to ride without one until I could get to a dealer.

I even did this with the windshield on my Road King and Heritages....

 

I am liking the zip tie trick until I can get a set of locks

 

won't fit in saddle bag

 

Is there a big market for hot backrests? Saddlebags, sure, but I doubt a backrest is on a thief's wish list...