How about having several meetings a month in some bunker as trial runs for the future.
While there may be some locations where "security" dictates that kingdom halls go on lock-down I have noticed that even in small, think 5,000 or less, population towns the kingdom halls are doing a lock-down for all meetings. If you are not there by conclusion of opening prayer you have to knock and be admitted by an elder. Practice for bunkers? IDK, but the ramping up of the "things in the world are soOOoo bad for us JDubs" and the increasing persecution complex they are being fed it would be easy for people to get paranoid about what the WTB&T$$ cult leaders are planning.
Personally I much rather expect the unexpected. No harm no foul if it doesn't happen, but prepared if it does.