If anyone offers to sell their Bitcoin to you simply because they know you one way the other, don't buy from them.
This days it is getting harder to trust anyone.
You can trade peer to peer online with an Escrow service for securing a trade for both the buyer and the seller, while you can do it offline, and trade in-person. The second type is offline and you can do it with people you know well, and surely do it at public places. Let's understand it right, you trade in-person at public places but the trade is private between you and your trade partner. No other people know about the trade, and you choose public locations to make sure that nothing like physical attacks can happen to you.
Surely if you can trade peer to peer, online, it's best method.