Like Jus Crusin said.....a half helmet is a tight fit for a saddlebag.
I lock my helmet to my front rotor with a NY forgetaboutit lock.
Secures my helmet and reminds me that I have a lock on my rotor before I try to leave.
I bought a helmet lock which I mounted to the crash bars on the right side. My half helmet will barely fit in my saddlebag, and that is if there is nothing else in there.