if a rock hits that it could jump its threads and then vibrate loose, the cap comes off and you loose everything inside (seen it happen)
...the only way to stop that is running all thread all the way thru the middle and securing both end with an ny-lock nut and washer, if you want to keep it in that location
i have another position option in my thread here
post 70 also if you look at mine i have made it lockable as well