That's a little bit super paranoid for localbitcoins trades! It's unlikely you will be doing high value trades in person in cash with it and if you must do due diligence and then some.

Basic common sense avoids majority of localbitcoin in person trade problems. Verified profile, reputation, reviews, public meeting place, escrow etc. Along with the other basic tips of not having everything in one wallet, don't have more than needed to trade on localbitcoins etc.

Bringing friends and guns is extreme! I guess justified if it's a trade in, say, Venezuela for $20k+ in USD. $USD is illegal there, government might arrest you for BTC trading and super hyper inflation has made $100 or equivalent goods value a small fortune some people will kill others for.