Wallet addresses are safe to display anywhere you would like to accept tips, payments, or donations. It is not possible to steal digital currency with a public address alone. The only way someone could access your funds would be if they had access to your account, or in the case of a non-hosted wallet, your private key.
Public Key (Public address): Similar to how an email can be given out to anyone to receive messages, a wallet address can be given out to receive payments.
Private Key: Much like one needs the password to an email account to be able to access and send a message from that email address, wallets have what is called a private key that is needed to send funds from a digital currency wallet.