Yes, use a password to protect it. It won’t make it as safe as non-wireless setup, but you still have to precautions.
BTW, did YWN just do a story on how the FBI raided the wrong house because the guy was using his neighbor’s wi-fi?….if you didn’t read it, John Doe was doing something he shouldn’t have been doing online & the FBI decided to pay him a visit. However the IP address & account info showed up as his neighbors, since that is the owner of the wi-fi that he was signed onto. It ended up the FBI busted down the wrong door…oooooops