The "go bag" thing was the WTS's (typically too little too late) response to Hurricane Katrina & the subsequent relocation of thousands of people. Congregations literally lost track of hundreds if not thousands of JWs who relocated, at least temporarily, to surrounding states.
This of course, cannot be - the WTS can't bear to lose control of their adherents even for a few months.
And, of course, it was a boon for anyone who wanted to fade - far easier to just disappear.
So, the reaction was that each congregation has to have a "disaster preparedness plan", each JW family should have a "go bag", each family is expected to provide a list of out-of-state contact numbers to the elders, etc.
It's actually a good idea - people really should be prepared to evacuate quickly if they live a potentially hazardous area - but the motivation of the WTS primarily is to make sure no one slips through their fingers.
And of course, the bonus effect is that the WTS can stoke the idea of "get your go bag ready - Armageddon's a comin'!"