Can you have same Bitcoin Address in 2 different wallets? Not the same wallet on different locations.

The reason I ask is that I am about to buy some bitcoins for cash and in order to transfer the bitcoins he will bring with him a paper wallet containing the bitcoin public and private keys.

He has told me to scan these into my blockchain.info app.

I just wondered if this a safe way to transfer bitcoins since he will have access to the private and public keys and could double spend the bitcoins.
Anyone with access to the private key can spend any bitcoins belonging to the public key address. 

Once you get the key from him, you should have blockchain "sweep" the balance at that address into a new address that only you have the key for.